Baked Haddock with roasted tomatoes, fennel and thyme- a simple, easy, healthy one-pot meal that can be made in 35 minutes! Gluten-free, Paleo, keto!
Here’s an easy delicious recipe for Baked Haddock with Roasted Tomatoes and Fennel. It’s a healthy “one-pot” meal that can be made with any white fish really ( cod, halibut, seabass, sablefish) and the roasted fennel with summer tomatoes, garlic, lemon and thyme is one of my favorite combinations.
Haddock, if unfamiliar, is a popular whitefish on the East Coast, known for its flaky clean texture, and low oil content, very similar to Atlantic cod. A family owned seafood company, Mazzetta Company sent me some of their Haddock to try, and it was fun experimenting with it, never having it before. Typically on the East Coast, it’s served “New England Style” with a breading of sorts, but I thought I put more of a Northwest spin on it this time.
The tomatoes and fennel become meltingly delicious in the oven, then the fish is nestled in them, and baked.
How to make Baked haddock
Preheat the oven to 400F and cut haddock filets into smaller portions.
Place in a bowl and toss with marinade ingredients. Set aside. You could marinate overnight.
While the fish is marinating, begin layering the onion, thinly sliced fennel and tomatoes.
Drizzle with olive oil, lemon, salt and pepper and roast in the oven until the fennel is tender, about 30 minutes.
Nestle the fish in the roasted tomatoes fennel mix, and place back into the oven for 7-9 minutes or until the fish is cooked to your liking.
When it comes out of the oven, squeeze with lemon and serve.
What to serve with Baked Haddock
- Black Rice
- Quinoa
- Roasted Garlic Mashed Potatoes
- Instant Pot Polenta | Pressure Cooker Polenta
- The Easiest Instant Pot Risotto Recipe
Enjoy the Baked Haddock and please let us know how you like it in the comments below!
More Fish Recipes you may like:
- 50+ Best Fish Recipes!
- Baked Cod with Asparagus, Lemon, Garlic & Thyme
- Baked Cod with Burst Tomatoes & Basil
- Baked Salmon with Dill Sauce and Asparagus
- Citrus Baked Salmon with Fingerlings

Baked Haddock
- Prep Time: 10 mins
- Cook Time: 45 mins
- Total Time: 55 mins
- Yield: 4
- Category: Main, fish, seafood,
- Method: baked
- Cuisine: Italian
Description
Baked Haddock with roasted tomatoes, fennel and thyme a simple, easy, healthy one-pot meal that can be made in 35 minutes! Gluten-free, Paleo, keto.
Ingredients
- 1 lb Haddock (or other white fish like cod, halibut, sable or bass)
- 1 1/2 tablespoon olive oil
- 3 cloves garlic-minced
- lemon zest from one lemon
- 1/2 teaspoon kosher salt
- 1/4 teaspoon cracked pepper
- 1 tablespoon thyme
- 1/2 of a sweet onion- thinly sliced
- pinch salt and pepper
- juice of one lemon
- 1 teaspoon olive oil
- 1 fennel bulb- very thinly sliced
- 1 1/2 lbs cherry, grape or baby heirloom tomatoes
- Garnish with Thyme Sprigs
Instructions
- Preheat oven to 400F
- Cut fish into 6-8 pieces. In a medium bowl, mix oil, garlic, salt, pepper, thyme and lemon zest. Toss with fish, set aside.
- In a lightly oiled baking dish, place onion slices on the bottom. Scatter sliced fennel over top. Drizzle with 1 teaspoon olive oil, lemon juice from ½ a lemon, and sprinkle with a generous 3 finger pinch of salt and pepper.Top with tomatoes.
- Place in the oven for 30-35 minutes, giving a good shake, halfway through. Place the white fish overtop, nestling among the tomatoes. Drizzle any left over marinade over the fish and tomatoes. Place back in the oven and cook 7-8 minutes or until fish cooks to desired done-ness.
- Remove from oven. Squeeze with remaining ½ lemon, scatter with thyme and serve.
Notes
Leftovers will keep up to 3 days in the fridge. Fish can be marinated overnight.
Nutrition
- Serving Size: 4 ounces
- Calories: 208
- Sugar: 8.7 g
- Sodium: 1020.2 mg
- Fat: 7.5 g
- Saturated Fat: 1.1 g
- Carbohydrates: 16.7 g
- Fiber: 4.1 g
- Protein: 21.1 g
- Cholesterol: 61.2 mg
Simple and delicious!
This recipe is amazing! I have never posted a comment about anything before, but I HAVE to say how much we love this recipe! I knew I liked all the ingredients and thought it looked interesting and worth trying. Despite the fact that it smelled wonderful while cooking, I wasn’t prepared for just how different and delicious it tasted. Awesome! Prep took me a little while the first time through, but now I am more organized with it, and it goes smoothly. Just love it!!
Shari thanks so much for you comment and Im so glad you enjoyed this!
Wow! Truly the best white fish recipe I have found yet – and I’ve been looking. Easy to assemble, full of flavor, low carb, low fat and low cost. Cooks quickly and minimal cleanup – one baking pan and one bowl. Excellent, thank you so much for sharing.
Lovely dish, easy to make and was perfect for a dinner party. Really pleased how it turned out and will cook again. Thank you
This was amazing! It was such a hit at my house, and the bonus part is it’s so simple to make. I did struggle cutting the fennel thinly in match stick style. I YouTubed it and couldn’t find a tutorial. How do you usually do it?
This was amazing!!! Such a hit at my house, and also sooo simple to make. I did struggle cut the fennel thinly in the match stick style. I YouTubed it but had a hard time finding a tutorial. How do you usually do it?
Sylvia, My husband and I really loved this! I liked how you feel ‘satisfied’ but not FULL [in the way that some dishes do.] Definitely a ‘do over’ meal!
Thanks for the comment and rating! Im so glad you enjoyed this!
Have never cooked fish in this way before .Will be trying this next week.
Easy and absolutely delicious! Was perfect for our dinner party, as I could roast the veggies well in advance, and then once guests arrived just plopped on the fish and put the whole thing back in the over until done. Next time I make this I will double the vegetables, as they do cook down quite a lot.
Thanks for this, I had never cooked with Fennel before and this recipe was a revelation.
Beautiful flavours and so appetising, will definately do it again, best wishes from England.
Thanks Dennis from England….glad you enjoyed!
Lovely dish with subtle flavours.
This was the first time I cooked haddock and it was fantastic. The fresh lemon and sprinkle of salt over everything at the end was a great touch. Thanks for sharing this!
Im so glad you enjoyed it Matt! The great thing is the dish works with most any white fish- so if you are in an area of the country where haddock isn’t available, cod, halibut or seabass work really well too!
.
I love this recipe! It’s become an easy staple in quick weeknight meals for us.
I do make some modicifications to my personal taste, and I’ll share for those that might wanna branch out: I add 3-5 cloves of roughly chopped garlic to the fennel and onion mix (love roasted garlic bits!), and let it all bake MUCH longer – this way, it gets really caramlized and contrasts the acidity of the lemon and tomatoes. The tomatoes also end up with nice bits of char to them. Sometimes I add some toasted pine nuts at the end, or my favorite, olives with the other veggies. Served with some very crispy roasted potatoes, and done!
I love how you made this your own. Great modifications. Do you add the fish later then?
.
This meal deserves it’s own mic drop!
I’m adding it to our usual meal rotation which is funny because I dislike fish. This is seriously delicious, and best of all, easy.
Added French bread and it made a perfect light meal.
Loved, loved, loved it!
Thanks Anita, Glad you enjoyed!!
Thank you for including a “jump to recipe” link on your web-pages! I asked for this in my feedback to your survey earlier this year. It makes it so much easier to navigate your site.
You are so welcome Rima- It took a while before I figured out how to do it, but it was a great idea!! If you have any others, please free to email me- you can always just hit “reply” to the weekly emails!
This is a lovely summer recipe. Tastes of the Mediterranean for us British..
I held off on making this because my enameled cast iron braiser is getting ready to be sent in for warranty service. I was surprised your pictures, which look terrific, do not match the equipment specifications called for in the recipe (baking dish). I’m usually a stickler for recipe directions when making a recipe the first time, but used a sheet pan to roast the vegetables; I was worried too much overlap would cause them to steam rather than roast. I used previously frozen Atlantic cod and it turned out really delicious. I also realized, by using a sheet pan, you could double the fish (and marinade) for larger parties and get a lot more mileage out of the veggies.
This recipe was recommended by a colleague at work. I don’t usually like to cook as I live alone and find it to be a chore, BUT this recipe will have me cooking in NO TIME. It’s just that good. I can’t get over how well all the flavours blend together and noticed that they tend to get better even better with time (good the first day, delish the second!) I’ve subsequently shared this recipe with other colleagues, one of which doesn’t like thyme and doesn’t like fennel and ended up loving it. Thanks!
Hi Julien, This makes me so happy!! I can’t tell you how satisfying it is to hear someone “who doesn’t like to cook” say they actually enjoyed cooking for a change….to me, this is the “why” behind the blog, I really want people to enjoy the process of cooking as much as I do…because it can be the best part of my day! Relaxing, fun, creative…I could go on and on….anyways, thank you so much for this, you made my morning!!
Delicious and so easy to make! This now on my favorites list. Can’t wait to make this again and share it with the whole family.
Im so glad you liked it!!
Thanks for this recipe. I made it the other day and it was so flavourful that am making it again at least two more times this week :). I had some day-old rice that I tossed in duringthe last 15 minutes and added some cubes of fresh mango I had in the fridge. Just really delicious. Thanks again.
So glad you enjoyed it Tamara…thanks for sharing and be sure to rate the recipe! I love that you added rice and mango!
Looks delicious! Fennel has been my secret ingredient lately.
I love using cast iron for a meal like this, and wouldn’t go the bakingdish route in the recipe.
Also with all the lovely flavors that should be developed in the bottom of this pan WHY would I need something as strong as thyme on that lovely mild whitefish?
I’ll report, when I have thyme, not.
This is so gorgeous, it stopped me in my tracks this morning. Who knew that one could crave haddock at 6:30am? Pinning!
Thanks Katie, you are so sweet! Hope all is well with you!
That looks so good! Did you use a cast-iron baking dish?
Yes, thanks, just my cast iron skillet.
I love this recipe. Thanks for sharing. Want to cook right now
thanks, have a great week!
Truly gorgeous, this looks like a great idea for intimate dinner parties. Love these colors and flavors!
Thanks Mary Frances, yes a good one for entertaining!