One-Pan Roast Salmon Leeks Onions

The first time I made this salmon dish was on a Tuesday evening when I wanted something that felt special but wouldnapost actually take forever. The leeks caramelized in ways I didnapost expect their sweetness balancing the bright parsley punch perfectly. My kitchen smelled like a really good restaurant and I kept checking the oven because I couldnapost believe something this simple could look so beautiful.

I served this to friends who swore they didnapost like leeks and they literally asked for seconds. The vegetables underneath catch all those delicious salmon juices while the dressing wakes everything up. One friend said it tasted like something from a restaurant except we were just sitting around my kitchen table in our regular clothes.

Ingredients

• 4 salmon fillets: Skin on helps keep the fish moist and protects it from direct heat plus it gets nicely crisp
• 2 large leeks: Slice them thick so they donapost completely disappear during roasting they become sweet and almost creamy
• 1 large red onion: Cut into wedges rather than dice so they hold their shape and develop those charred edges
• 2 tbsp olive oil: This coats the vegetables and helps them roast rather than steam
• 1/2 tsp sea salt: Enhances natural sweetness of the leeks as they caramelize
• 1/4 tsp black pepper: Adds a subtle warmth that balances the bright dressing
• 1 lemon: Thin slices over the salmon keep it moist and add a gentle citrus perfume
• 1 cup fresh parsley: Use flat leaf for better flavor and chop it finely so the dressing is vibrant and green
• 1 small garlic clove: Mince this really small so it disperses evenly through the dressing
• 1/2 tsp Dijon mustard: This acts as the emulsifier helping oil and lemon juice come together properly
• 1 tsp capers: Chop these so they disperse their briny punch throughout every bite
• 1/2 tsp lemon zest: This gives the dressing an aromatic brightness that juice alone cannot provide
• 3 tbsp extra virgin olive oil: Use good quality oil here since the dressing is so simple and uncooked
• 1 tbsp fresh lemon juice: Acid cuts through the rich salmon and ties everything together

Instructions

Get your oven ready:

Preheat to 400°F so the salmon roasts rather than bakes giving you those nicely browned edges.

Prep the vegetables first:

Spread leeks and onion on a large baking sheet in one crowded layer then drizzle with oil and season well before tossing everything together with your hands.

Give vegetables a head start:

Roast them for 10 minutes so they begin to soften and develop some color before the salmon goes in.

Add the salmon:

Nestle the fillets skin side down among the partially cooked vegetables and arrange lemon slices over each piece of fish.

Finish roasting:

Return to the oven for 12 to 15 minutes until the salmon flakes easily and vegetables are tender and golden in spots.

Make the dressing while things roast:

Whisk together parsley garlic Dijon capers lemon zest olive oil and lemon juice until combined then season to taste.

Plate and dress:

Transfer salmon and vegetables to warm plates then spoon that bright green parsley dressing generously over everything.

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This recipe has become my go to when I want to eat well but barely feel like I cooked. There is something about the way the sweet roasted vegetables taste with that punchy herby dressing that makes the whole plate feel balanced. I make it on weeknights now without even really thinking about the menu.

Making It Your Own

Sometimes I add capers directly to the roasting vegetables instead of just the dressing for these salty bursts throughout. Other times I throw in some cherry tomatoes if I have them around they burst and become jammy in the oven. The dressing can take other soft herbs too like basil or tarragon if parsley feels too predictable.

Getting The Timing Right

Once the salmon hits the hot sheet pan it cooks really fast so watch closely after the 10 minute mark. I check by gently pressing the thickest part with my finger it should feel firm but still have a little give. Remember the fish keeps cooking slightly once it comes out of the oven so do not wait until it looks completely done.

Serving Suggestions

This needs something to soak up all those delicious pan juices and extra dressing. I usually serve it with steamed rice or roasted potatoes but even just good crusty bread works. A simple arugula salad dressed with nothing but lemon and olive oil balances the richness perfectly.

• Warm your plates before serving so the fish stays hot longer
• Have everything plated before drizzling the dressing so it stays bright and fresh
• Leftovers keep well but the dressing is best made fresh

Save

That first bite of tender salmon with sweet roasted leek and bright parsley dressing is exactly the kind of dinner that makes cooking feel worth it.

Recipe FAQs

→ What kind of salmon is best for roasting?

For roasting, look for fresh salmon fillets that are about 1-inch thick, either skin-on or skin-off. Skin-on helps keep the fish moist and prevents sticking to the pan. Sockeye or Atlantic salmon are popular choices, but any good quality fillet will work beautifully.

→ How can I tell if the salmon is perfectly cooked?

Salmon is cooked when it flakes easily with a fork and the internal temperature reaches 145°F (63°C). The flesh should look opaque throughout but still appear moist. Avoid overcooking, as this can make the salmon dry.

→ Can I prepare the parsley dressing in advance?

Yes, the parsley dressing can be prepared up to 2-3 days in advance and stored in an airtight container in the refrigerator. Allow it to come to room temperature and give it a good stir before serving, as the olive oil may solidify slightly when chilled.

→ What other vegetables could I roast with the salmon?

This dish is quite versatile! Feel free to substitute or add other quick-roasting vegetables like asparagus, bell peppers (sliced), cherry tomatoes, or zucchini. Just ensure they are cut into similar sizes so they cook evenly with the leeks and onions.

→ Is this dish suitable for meal prepping?

While best enjoyed fresh, this salmon dish can be prepped for lunch the next day. Store the salmon and vegetables separately from the dressing. Reheat the salmon and vegetables gently, then add the fresh dressing just before serving to maintain its vibrant flavor and texture.

→ Can I use frozen salmon for this preparation?

Absolutely! If using frozen salmon, ensure it is fully thawed in the refrigerator overnight before cooking. Pat the fillets dry thoroughly with paper towels before seasoning and roasting to achieve the best texture and avoid excess moisture.