Roasted Brussels Sprouts Equipment Required Roasting Pan Ingredients · brussels sprouts, cleaned, cut in half · salt · pepper · olive oil · 1 onion, sliced · several fat cloves garlic Directions Spray the roasting pan with non-stick cooking spray. Start the oven preheating at 450 degrees. Put the sprouts, onion and garlic in the roasting pan. Add a little olive oil and toss until everything is nicely coated.