Preheat the oven to 400°.
Place filets on a greased baking sheet.
Stir together butter, garlic, and parsley and pour over the fish.
Set in the refrigerator until ready to cook.
Brush olive oil on a second baking sheet.
Toss sweet potato cubes with a drizzle of olive oil, salt, and pepper.
Place in the oven for 15 minutes.
Meanwhile, clean, stem, and cut brussels sprouts in half.
Drizzle with olive oil, salt, and pepper.
Pull the sweet potato cubes from the oven and add the brussels sprouts to the pan.
Return to the oven and add the pan of fish to the oven.
Cook for 15-20 minutes, until the salmon is cooked through, and the squash is fork-tender.