Preheat oven to 400∘F (200∘C). Line a baking sheet with parchment paper.
Place salmon fillet on one side of the baking sheet. Drizzle with 1/2 teaspoon of olive oil and season with salt, pepper, and 1/4 teaspoon of rosemary
Arrange asparagus on the other side of the baking sheet. Drizzle with the remaining 1/2 teaspoon of olive oil and season with salt, pepper, and garlic powder.
Bake for 15-20 minutes, or until salmon is cooked through and flakes easily with a fork, and asparagus is tender-crisp.
Serve immediately with a lemon wedge.