Preheat the oven to 425 F and line a baking sheet with parchment paper.
Wash the Brussels sprouts and asparagus well. Remove the ends of both vegetables. Slice the Brussels sprouts in half. You can keep the asparagus long or cut in half.
Place skinless salmon filet lengthwise in the center of your baking pan. Arrange the Brussels sprouts and asparagus around the salmon. Using a brush, lightly drizzle the veggies with the olive oil mix. You can add a little olive oil to the salmon and sprinkle with pepper. Scatter slices of lemon on the pan.
Bake for around 12-15 minutes depending on how well-done you like your salmon cooked, then turn the oven to a broil setting for around 2-3 minutes to give the salmon a final golden glow. Serve immediately.