Baked Mustard-Crusted Salmon with Asparagus and Tarragon

epicurious.com 
http://www.epicurious.com/recipes/food/views/baked-mustard-crusted-salmon-with-asparagus-and-tarragon-56389444

YIELD: Serves 4
ACTIVE TIME: 8 minutes
TOTAL TIME: 22 minutes
INGREDIENTS

1 bunch thin asparagus (about 1 pound), trimmed
3 tablespoons olive oil, divided
3/4 teaspoon kosher salt, divided
1/2 teaspoon freshly ground black pepper, divided
4 (6-ounce) skin-on salmon fillets
8 teaspoons country-style or whole-grain Dijon mustard
3 tablespoons panko (Japanese breadcrumbs)
1/4 teaspoon smoked paprika
2 tablespoons chopped fresh tarragon
PREPARATION

Preheat oven to 275°F. Line a rimmed baking sheet with parchment paper. Toss asparagus with 2 Tbsp. oil, 1/2 tsp. salt, and 1/4 tsp. pepper on prepared sheet, then arrange in a single layer on one half of baking sheet. Bake asparagus 5 minutes.

Meanwhile, spread each salmon fillet with 2 tsp. mustard. Sprinkle fillets with 1/4 tsp. salt and 1/4 tsp. pepper total. Toss panko with remaining 1 Tbsp. oil in a small bowl. Sprinkle panko mixture evenly onto salmon fillets, then dust with smoked paprika.

After asparagus has baked for 5 minutes, remove baking sheet from oven. Place prepared salmon fillets skin side down on empty half of baking sheet. Return to oven and bake until salmon is firm but still pink in the center and asparagus is tender, 14–16 minutes more for medium rare salmon. Divide salmon and asparagus among four plates and top with tarragon.

cooks' note:
If asparagus spears are thick, increase initial baking time to 10 minutes before adding the salmon fillets to the baking sheet. If you prefer your salmon more well done, increase cooking time by 5 minutes and check for doneness.