Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Pat the salmon fillet dry with a paper towel and place it on one side of the baking sheet.
In a small mixing bowl, whisk together the Dijon mustard, lemon juice, and garlic powder until well combined.
Spread the mustard mixture evenly over the top of the salmon fillet using a spoon or pastry brush.
Finely chop the fresh parsley and combine it in a small dish with the almond flour, sea salt, and black pepper.
Press the almond-herb mixture firmly onto the mustard-coated salmon to create an even crust.
Trim the woody ends off the asparagus spears and place them on the other side of the baking sheet.
Drizzle the asparagus with olive oil and toss to coat, spreading them out in a single layer.
Bake for 12 to 15 minutes, or until the salmon is opaque and flakes easily with a fork and the asparagus is tender-crisp.
Serve immediately, optionally garnished with an extra squeeze of fresh lemon.