Toss Brussels sprouts with olive oil, salt, and pepper. Place Brussels sprouts in a greased baking dish. Gently place sausage links on top of Brussels sprouts. Cover with foil and bake at 400 degrees for 30 minutes. Remove cover; continue to bake for 10-15 minutes or until sausage links reach an internal temperature of 165 degrees.
Brush sausage links and Brussels sprouts with the maple syrup and Dijon mustard mixture. Cook for an additional five minutes to allow sauce to brown.