This Baked Salmon & Onions Casserole is an unusual Mediterranean casserole, but believe me when I say that everyone will be asking for seconds. It’s not an easy dish to cook but with few tips you can make this casserole like a pro. Plus, I added a short video to make it a little easier to explain:).
This casserole is Mediterranean Diet friendly. My favorite quality is that it uses all fresh, not processed ingredients.

Traditional Onions Casserole
My home country of Albania has a rich culinary history. We bake onion casseroles in different regions of the country. However, the coastal areas tend to bake this dish with fish while the Northern regions make it with veal, beef or lamb. Each one is amazing on its own and hope to cook more versions of this dish to share with you all.
Salmon is not the typical fish we use to cook this dish. Most typically if we are baking this onion casserole with fish, we use Carp fish (in Albanian we call this Krap) or Trout (trofta). In Albanian we would call this dish ‘Tave me qepe dhe salmon’!
Cooking the Onions
Onions are the key ingredient for this dish. First you need a lot of them, I used about 3 lbs onions. You might think that’s an insane amount 🙂 and yes maybe it is. But believe me you won’t regret it when you’re eating this dish!
Onions need to be cooked thoroughly. It really makes or break the recipe!! I’m warning you that this dish requires patience:).
When you’re cooking the onions, you just stir occasionally and let them sweat. It’s a slow process. It helps me to either keep a show running on TV or listen to music while I cook so I don’t rush. I tend to want to make this process faster and believe me, on this dish you need to slow down, not cut corners.
Cook the onions until the volume has gone down to half. Then you can start adding ingredients as shown in the video. Then you let it cook some more:).
Cooking Onions Volume Goes Down as Onions Cook
Tips & Notes
Here are some additional tips to help cook this onion casserole to perfection.
- Marinate the salmon with olive oil, lemon and salt while you cook the onions. Place the container with salmon and marinate (covered in a plastic wrap) in the refrigerator for the duration of time it take to cook the onions.
- When you are cutting the onions, chop them roughly. No need to be picky here. This is one of the steps where you can just go as fast as you can. Onions don’t need to be minced, just chopped in big slices.
- I use a dutch oven to cook the onions, just a regular non stick pot would suffice.
- Baking this dish takes about 45 minutes. Nestle the salmon into the onion mix before baking. This will help that the casserole cooks homogeneously and salmon doesn’t overcook.
How to Serve this Casserole?
I usually serve this casserole with slices of bread and a simple salad. You don’t want complex flavors added in.
Personally I enjoy this dish with a glass of either Chardonnay or Pinot Noir. Usually I don’t go for reds with salmon, but it really makes sense with this dish. Must be because of the onions.
Baked Salmon & Onions Casserole
Equipment
- 1 large pot
- 1 baking tray
- Wooden spoon
Ingredients
- 4 salmon fillets about 6 ounces each
- 3 lbs onions (usually yellow large onions) ~ 1.4 kg
- 3 tomatoes
- 4 bay leaves
- 1 lemon
- 1 tbsp salt I prefer Mediterranean Sea Salt
- 1 tbsp oregano
- 1 tsp black pepper
- 4 tbsps olive oil (divided)
- 1 cup water
Instructions
- Peel the onions and place them in a big bowl with water. Puree the tomatoes using a food processor.
- Cut lemon in half. Drizzle salmon with lemon juice (from half a lemon), 1 tbsp of olive oil and some salt. Cover with plastic wrap and place in refrigerator.
- Chop the onions roughly, no mincing, they have to be big slices.
- Add 3 tbsps of olive oil to a large pot in medium heat (I prefer a dutch oven 6 qt but if you don't have a dutch oven, a large pot is perfect too).
- Add onions to the pot. Stir slowly to turn them from bottom to top occasionally. Slowly the onions will become translucent and release their own liquid. Continue stirring.
- Onions' volume will be reduced in half at about half hour mark in the cooking process. Add salt, oregano, black pepper and bay leaves. Mix well and let cook some more. Stir occasionally with a wooden spoon to ensure that the bottom doesn't get burned.
- Once you see that the mix is getting dry and can start sticking to the bottom add the tomato puree and 1 cup of water. Mix well and cover the pot. Let cook for another half an hour or so.
- Slice the left over half lemon.
- Once the onion mix is cooked thoroughly and become a homogenous mass, then pour it into the baking tray. Add salmon pieces on top and push them down a little bit into the mix so they don't burn while baking. Garnish with lemon pieces on top of salmon.
- Bake at 400 degrees F (~ 200 degrees C) for about 45 minutes. Salmon will be soft and tasty on the inside and have a crust on the outside. Serve with salad and bread! Enjoy:)
Video
Notes
- Some onions take longer to cook. Cook them longer if needed to achieve the right taste. The onions have to be soft.
Nutrition Label
Nutrition
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More recipes?
I have several more seafood recipes, feel free to check them out.
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