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Walnut Olive Slow Roasted Halibut

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walnut olive halibut

Decadent flaky fish baked in a spiced lemon oil finished off with a rich and briney gremolata: this Walnut Olive Slow Roasted Halibut is the easiest impressive dish.

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In my opinion, everyone needs a good dinner party staple in their repertoire. Whether you’re having friends over, in charge of Christmas dinner, or just feeling like whipping up a classy dish, this Walnut Olive Slow Roasted Halibut is really the answer to all of your problems. Slowly baked in tons of herbaceous juices over thinly sliced onion and dressed with a persillade type of topping — this truly tastes like it is straight off of a Michelin star restaurant. Still, this fish is probably one of the easiest dishes you’ll ever make. Delicious, simple, healthy, elegant — what more could you ask for? You have to give this recipe a try!!

The breakdown…

This Walnut Olive Slow Roasted Halibut recipe starts off by making the quick seasoned oil to pour over that fish. For this recipe, and really any fish recipe, I recommend using a high quality olive oil. By this, I mean you should use something extra flavorful and strong, as opposed to your everyday, cheaper olive oil. With a robust flavor from your oil, you truly get that good olive taste that sinks into the fish and transforms the palette. I often find my favorite oils at my local Greek store or farmer’s market, but you could definitely find some good brands at the grocery store, too. 

All this said, if you don’t have access to a good olive oil, don’t fret — your fish will still be plenty flavorful. In fact, with the addition of smoked paprika, dried parsley, cumin, lemon juice, salt, and pepper, this oil really turns into a flavorful marinade of sorts. The flavors are almost Middle Eastern, yet also have a bit of a Greek flair — pairing wonderfully with the olive walnut topping. It’s also pretty heavy on the lemon juice, which brings a little brightness to the fish… because, pro tip: if you are new to cooking or just don’t know where to start with fish, always start with a little lemon juice — it truly brings out all the good flavors of a delicate fish!!

Decadent flaky fish baked in a spiced lemon oil finished off with a rich an

get roasting!

Once you have that marinade all good to go, simply layer some thinly sliced onions and the fish into a 9×13 baking dish, top it with that good mixture, and pop it into the oven. Super simple, I know!! Really, though, with a fish as delicious as halibut, you don’t need to go crazy with the searing, frying, or blackening. Still,  I like to switch my oven to broil for the last few minutes of the cooking time. This makes the top of the halibut get a nice crisp while the bottom of the fish is still super juicy and moist. 

Or, if you didn’t want to go with halibut, this Walnut Olive Slow Roasted Halibut recipe can easily be done with another fish. Grouper, salmon, and bass would be my go-to substitutions, but you could really go with whatever mild fish you love. But, just note that different types of fish constitute different cooking times, so be careful to not roast your fish for too long!!

that olive walnut topping…

While the fish is in the oven, it’s time to get cracking on that olive walnut topping. With a base of some more good olive oil, this topping could really be seen as more of a persillade, gremolata, or even a chimichurri of sorts. You’ve got those vinegars for some tang, but also some honey to even things out. My favorite vinegars here are half champagne vinegar which is a little milder and sweeter, and half white wine vinegar with a stronger, more  classic vinegar taste. I also love to use honey as my go-to sweetener (if you can’t tell from my other recipes, lol), simply because it’s my personal preference. 

With both of these ingredients, however, you could easily make substitutions. Red wine vinegar or sherry vinegar would both be delicious. Or, you could even do all champagne vinegar or all white wine vinegar — it’s up to you! And, when it comes to honey, sugar or pure maple syrup would also be delicious, so go with what you love. Really, the moral of the story is that you need a good bite from vinegar and a good contrast from a sweetener, but the actual ingredients come down to personal preference! 

Decadent flaky fish baked in a spiced lemon oil finished off with a rich an

all the goods…

To that base, you’ve got to go ahead and add all the goods: toasted chopped walnuts, fresh parsley, and castelvetrano olives. Wow. I’m literally drooling just thinking about this. Toasted walnuts have been my recent obsession… like they are seriously underrated in my opinion. And, if you’ve seen my post on my Lemon Olive and Herb Roasted Chicken Bowls, you know castelvetrano olives have my heart. Then, with the addition of some parsley, these fatty, smooth components completely come together to make the most fresh and flavorful topping you will ever eat. Like, for real, I eat this stuff straight with a fork — it’s a miracle we even have enough left to top off the fish!!

how to serve this up!!

Once you have everything all pulled together, though, this Walnut Olive Slow Roasted Halibut really is a work of art. You could really serve this up for any occasion — fancy or not. I love making this for family dinners, as my sister is a self-proclaimed pescatarian at the moment. But, this dish is definitely classy enough to impress guests. Serve it with some jazzed up couscous, asparagus, or The Best Brussels Sprouts You Will Ever Eat, and it’s sure to be a winner. You could even go with a mashed sweet potato, polenta, or my Creamy Mashed Cauliflower for a bit of a different side. 

Really, though, however, whenever, and to whomever you serve this Walnut Olive Slow Roasted Halibut to, I know it will be a hit! Let me know what you think in the comments below… enjoy:)))

Walnut Olive Slow Roasted Halibut

Recipe by Annie PatrickCourse: Main CourseDifficulty: Easy
Servings

4

servings
Prep time

10

minutes
Cooking time

20

minutes
Total time

30

minutes

Decadent flaky fish baked in a spiced lemon oil finished off with a rich and briney gremolata: this Walnut Olive Slow Roasted Halibut is the easiest impressive dish.

Ingredients

  • roasted halibut:
  • ⅓ cup olive oil

  • 1 tbsp smoked paprika

  • 2 tsp dried parsley

  • ½ tsp cumin

  • 2 medium lemons, juiced

  • 1 tsp salt

  • Freshly ground pepper

  • 1 white onion, thinly sliced

  • 2 lb halibut, cut into 4 fillets

  • olive walnut topping:
  • ¼ cup olive oil

  • 1 tsp honey

  • 2 tbsp champagne vinegar

  • 2 tbsp white wine vinegar

  • Salt, to taste

  • ¼ cup walnuts, toasted and roughly chopped

  • ½ cup fresh parsley, chopped

  • ½ cup castelvetrano olives, pitted and chopped

Instructions

  • Preheat the oven to 350 degrees.
  • In a small bowl, whisk the ⅓ cup olive oil, smoked paprika, dried parsley, cumin, lemon juice, salt, and pepper. Layer the onions over the bottom of a 9×13 inch baking dish, then arrange the fish fillets over top. Pour the prepared olive oil mixture over the fish. Transfer the dish to the oven and bake for about 20 minutes, or until the fish is opaque and flakes easily. For an extra crisp topping, switch the oven to broil for the last 3 minutes. (The baking time may vary depending on the thickness of your fish)
  • Meanwhile, in a small bowl, whisk the ¼ cup olive oil, honey, champagne vinegar, white wine vinegar, and salt. Mix in the walnuts, fresh parsley, and castelvetrano olives.
  • Once the fish is cooked through and flaky, pour the walnut olive mixture over the fish. Serve warm and enjoy!
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