Oven-Roasted Rosemary Halibut with Fresh Tomato-Zucchini Sauce

Shown here with white beans.
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It’s easy to avoid cooking fish or to cook it as simply as we can possibly figure because we’re unsure of our fish-cooking abilities. Or maybe fresh fish isn’t so available and feels expensive — especially in a land-locked state. Perhaps there’s a fear factor involved or we wonder, “Is fish really good for us?” How fast does it go bad? When is it done? How do I not overcook it? So we go with grilled wild salmon once a month in good weather. Salt, pepper, lemon. Air Fried fish and chips might be a step up. A pound of shrimp for Christmas Eve. Truth to tell, fish is good for us, is readily available nationwide (even if frozen), and is the original fast –and easy — food. Lots of people order fish from restaurant menus, but hesitate to cook much at home. Want to change that at your house?

If you’re looking for a way to increase your fish intake and expand your fish-cooking repertoire, try my Oven-Roasted Rosemary Halibut with Fresh Tomato-Zucchini Sauce. The perfect family night fish dinner, this recipe doubles easily to feed some friends for whom you’re longing to serve something different and so very scrumptious. Both the sauce and the fish cook in a matter of minutes, so dinner is done in the flashiest of flashes. It’s also finally cooler weather — time for turning on your oven and tossing the very best things into it. Those would include the “king of white fish,” halibut, though you could certainly swap in any white fish you can find. Listen. Tender and moist lemon and rosemary-scented white fish on a gently seasoned bed of white beans or rice, topped with briny-garlicky scratch tomato sauce and a handful of fresh basil leaves for happiness, balance, and texture. There’s just a touch of heat to keep you interested and what about a few kalamata olives for drama? Did I mention this fish meal craves red wine? Yep, I promise that’s the truth. Sure and now you want to try it out ahead of time. I’ll hold your virtual hand while you do. Print the recipe and read along while you look over the pictures below. (Note: photos and captions are best viewed on a computer.)

Here we go:

Now that you’ve got it all figured out (right?!), it’s time to try this:

You can eat the crispy little rosemary leaves with your fish. Yum!

Oven-Roasted Rosemary Halibut with Fresh Tomato-Zucchini Sauce

For a beautiful and delicious, company-worthy but family-friendly dinner, this recipe is easy and quick to prepare and serve with its puttanesca-like flavors. I like it on a bed of either parsley rice or white beans, but you could serve it on quinoa, pasta, mashed potatoes, or all by itself with some crusty bread to sop up the fragrant sauce. If you are making rice, etc., begin that first as the sauce and fish are quick. That said, the sauce could be cooked earlier in the day (or the day before), then cooled and stored in the fridge. Just reheat gently it while the fish roasts in the oven. Two very hungry people might eat all of this, but served on rice, etc., it should feed 3 — or perhaps even four smaller appetites.
2-3 servings



  • 1 tablespoon EACH salted butter and olive oil
  • Pinch crushed red pepper
  • ¼ cup chopped red onion (You’ll use the rest for the fish.)
  • 3 whole cloves garlic, peeled
  • 1 small zucchini, cut into medium dice
  • ¼ fresh lemon (You'll use the rest for the fish.)
  • 6-8 Roma tomatoes –about a pound, chopped (or a 15-ounce can chopped tomatoes)
  • ¼ teaspoon EACH kosher salt and fresh ground black pepper
  • Pinch granulated sugar
  • ½ cup sliced kalamata olives
  • 2 tablespoons chopped fresh basil (You’ll need more for garnish.)


  • 1 – 1 1/4 pound halibut fillet, skinned and patted dry with paper towels
  • Olive oil
  • Kosher salt and fresh ground pepper
  • 1 lemon, sliced
  • ½ small red onion, cut into large dice
  • 6 small sprigs fresh rosemary (sub several pinches of dry rosemary)


  • Hot rice with parsley, mashed potatoes, white beans with rosemary, etc.– optional
  • Chopped or torn fresh basil/don't chop if small leaves (sub grated Parmigiano-Reggiano)
  • Freshly ground black pepper


  • PREPARATION: Preheat oven to 400 degrees F. Set rack at center. Line a rimmed baking sheet with parchment paper or foil.
  • MAKE THE TOMATO-ZUCCHINI SAUCE: Heat medium saucepan or skillet over medium high flame and add the crushed red pepper, cooking for 30 seconds. Tip in the onion and cook, stirring, for 3-4 minutes. Add whole garlic cloves, zucchini, and lemon. Cook another 5-6 minutes until zucchini is softening. Stir in tomatoes, salt, pepper, and sugar. Reduce heat and simmer for 10 minutes or until vegetables are all tender, adding olives and basil for the last minute or so. If using fresh tomatoes, add a little water if sauce is drying before it's done. Taste and adjust seasonings. Cover to keep warm while you cook the fish.
  • ROAST THE HALIBUT: Drizzle a tablespoon or two of olive oil down the center of the lined pan about the shape of the fish fillet. Place three slices of lemon evenly spaced down the center of the oil silhouette and top each with a little chopped onion and a sprig of rosemary. Add the fish and drizzle it with another tablespoon or two of oil. Sprinkle with salt and pepper. Top the fish with another 3 slices lemon, some onion, and another sprig of rosemary. Roast 10-15 minutes or until barely opaque, but moist. Begin checking for doneness at 10 min. If an end of the fillet is done before the center, you can carve that and plate it, returning the remainder to the oven for a few more minutes.  (See blog under TIPS for how to know when fish is done.)
  • SERVING: Divide the fish, lemon slices, onions, and rosemary sprigs among 3-4 plates or dinner bowls (on rice, etc., if using) and top with a scoop of tomato sauce. Garnish with a small handful of basil leaves. Grind a little pepper over all and serve hot, warm or at room temperature. Whoever gets the lemon in the tomato sauce does the dishes. Store leftovers well wrapped in the refrigerator for a day. Do not freeze.


COOK’S NOTES: If you’d like this for a larger group, double the recipe and cook both pans of fish at once, rotating them both front to back and switching shelves halfway through the roasting time.
If you have no olives, some capers might be a good substitution – or even a splash of red wine vinegar once the sauce is off the heat.
Copyright Alyce Morgan, 2021. All rights reserved.

I’m crazy about fish and tomatoes, so if you are, too, you might also like my SALMON PUTTANESCA:



Is the fish done? The rule of thumb for fish is 10 minutes per inch. The problem being, #1 at what temperature and #2 is the fillet an inch thick and, if so, is it the same thickness all over? You’ll have to decide if the fish is done by checking the thickest part. The thinner ends will be done before the center cuts. The fish will also continue to cook bit after it’s out of the oven. While, to me, a cooked fish is nearly opaque, almost firm, and no longer translucent, it should still be somewhat moist if not literally juicy, at the center. Here are what some other folks say about the issue, though Alyce would take this halibut for done at 135 degrees F to insure it didn’t overcook.

Use the tip of a small knife to peek at the interior of the fish. Many cookbooks tell you to cook fish until it flakes; this is too long. Once it flakes, the fish has lost too much moisture and will be dry and bland. As you peek, see how easily the fish gives way. It should gently resist flaking but show signs of firming. If the fish is on the bone, the flesh should lightly resist pulling away from the bone.    ~FINE COOKING

While the fork test and opaque color are excellent giveaways that fish is done cooking, the U.S. Food and Drug Administration (FDA) recommends a safe temperature for cooked fish of 145°F. Use an instant-read thermometer. ~BHG 

CHANGE IT UP: Any white fish would work here, as would grilled or oven-roasted shrimp. Eggplant will sub for zucchini — or a combination would be nice, too. No fresh basil? Use dry basil in the sauce and fresh parsley for serving. Fresh rosemary unavailable? Sub a good pinch of dry rosemary rubbed between your fingers to release its oils for each small sprig. Easiest/fastest beds for the fish if you’re a tired cook: microwave a package of Seeds of Change Quinoa and Brown Rice or…. use canned, drained, heated and seasoned cannellini beans. Slowest bed for the fish, scratch white beans: Slow Cooker White Beans with Lemon and Rosemary. I made a pound of white beans in a 6-quart pot on top of the stove seasoned with only onion, whole cloves of garlic, 2 sprigs rosemary, a shake or two of hot sauce, salt and pepper. They were perfect and there were plenty leftover for lunch. 19 grams of fiber in a cup of white beans — talk about increasing the health of this meal.

WINE: This is a great example of my, “pair the prep and not the protein.” It’s white fish, but you serve up a not-too-heavy Italian red with this and be glad you did. Montepulciano would be right up its alley.

DESSERT: A great time to serve a caloric dessert since you’re serving fish, but consider a nice cup of decaf espresso, some biscotti (homemade is easy, but buy some if you’re short on time), and a wee dram of Vin Santo.

REDUCING WASTE: There’s little worry you’ll have too much food or need to worry about leftovers here. An extra small piece should simply be eaten cold out of the fridge for lunch the next day–no need to heat. If there is extra sauce, it is scrumptious on the beans, particularly, or even the rice or crostini.

Last all-from-our-deck-garden salad of the year. Sniff.
Aspen time in the mountains.


Below: You might remember our little zippy chipmunk friend, Alvin— I worried he was alone as he has been just that for two years. The other day, he brought a friend to visit. Offspring, lover, roommate? Who knows? I’m not sure as it’s so difficult to really see them up against the wooden poles and bushes, but one may have been feeding the other! Look closely.

Above and Below: Still have green tomatoes? I made this Roasted Cider-Brined Pork Loin & Green Tomato Chutney in my slow cooker the other day and served it on rice with grilled zucchini. Found it in an old COOKING LIGHT slow cooker magazine. There’s a paywall to access it online, but you can follow the oven version from My Recipes. I cooked the pork and the chutney for 7 hours on low, took the chutney out and simmered it on the stove while leaving the meat on “warm.” The wonky directions had you slice the pork, leave it sit, and cook the chutney on high in the slow cooker for another 1.5 hours! Hello?

below: Went to the mountains last Monday to see the aspens changing and while I got lots of pretty photos, this one –not so big on the golden leaves — struck me. I took it driving back down the pass coming out of Woodland Park. It features the backside of Pike’s Peak. Lunch? Wanted to do Wines of Colorado, but they were sadly closed for a couple of days and are up for sale, more’s the pity. Instead we stopped at BierWerks in Woodland Park and sat outside for a tasty brat and brew. I’m not a big bratwurst sandwich fan, but these were good — a pork and veal mixture. If you’re not into brats, there’s often a food truck in the parking lot. Think pizza or BBQ.

In memoriam, my sister Jean Marie Gottardo — here at right several years ago with my daughter Emily and me. If you’re the praying type, I would appreciate prayers for my family now and on-going.

Thanks for spending time in my kitchen with me; you rock!

Be well and cook on,


3 thoughts on “Oven-Roasted Rosemary Halibut with Fresh Tomato-Zucchini Sauce

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