Preheat oven to 400°F (200°C) and line a sheet pan with parchment paper.
Prep the veggies – Toss butternut squash and Brussels sprouts with 1 tbsp olive oil, maple syrup, garlic powder, smoked paprika, salt, and pepper. Spread evenly on the sheet pan and roast for 12 to 15 minutes.
Prepare the salmon – While veggies roast, mix 1 tbsp olive oil, Dijon mustard, salt, pepper, and thyme. Brush over salmon fillets.
Add salmon to the pan – Push veggies to one side and place salmon fillets on the pan. Roast for 12-15 minutes or until salmon flakes easily with a fork and the internal temperature is at least 145 degrees F.