Preheat your oven to 400 degrees.
Cut two pieces of foil large enough to hold each piece of salmon and the asparagus and still close at the top. This will vary depending on the size of your fillet and the length of your asparagus. Fold each of the sides upward so they form a small “boat” and place them on the baking sheet.
Thinly slice your purple sweet potato, I used a slicer here but it isn't necessary, just ensure the potatoes are thin so they cook at the same rate as the salmon.
Peel and eighth the pearl onion (quarter each half).
Peel, smash and roughly chop the garlic clove.
Cut approximately 1⁄2 inch off the bottom of the asparagus stalks.
Add the potatoes to the medium mixing bowl and toss in preferred oil, salt, and pepper. Be careful not to add too much oil as the salmon’s natural oils will release over the potatoes while it bakes. Use just enough to coat the potatoes so the seasoning sticks!
Create a small layer of potatoes in each of the foil boats ensuring not to overfill so the sides of the foil still close.
Add the asparagus to the medium mixing bowl and toss in preferred oil, salt, and pepper.
Add the asparagus, garlic, and 1/2 of the pearl onion to each foil boat.
Lay the salmon filet over the potatoes, lightly season it with salt and pepper.
Add 1⁄4 cup of basil pesto to a small bowl. Brush (or use the back of a spoon to “brush”) the pesto over the top of the salmon.
Close all foil edges and place the baking sheet in the oven for 25-30 minutes, check on the salmon at the 25-minute mark.