Gather the ingredients needed.
Preheat the oven to 350° and spray a cookie sheet with nonstick cooking spray.
Place the salmon on one end of the pan, slightly spaced apart, and the asparagus on the other end. Pat the salmon dry with a paper towel.
Melt 4 tablespoons of butter and drizzle over the fish and the asparagus.
Sprinkle the chili powder, salt and pepper over the fish and asparagus.
Drizzle the lemon juice over the fish and asparagus and sprinkle with the lemon zest.
Let the fish sit for 5 minutes with the lemon juice on it.
Divide the remaining butter into 4 pieces. Place a pat of butter on each end of the fish.
Add lemon zest or a slice of lemon on the butter. Sprinkle with some parsley.
Place the pan in the oven and set the timer for 11 minutes. Remove from the oven and let the fish rest for 5 minutes before serving.
Sprinkle with any remaining parsley.
Serve while warm.
Enjoy every bite.