Pull sausages from the fridge about 10 minutes before cooking so they're not ice-cold. Pat dry with a paper towel to help browning. If roasting with veg, cut dense items like potatoes into 1-inch pieces. Lightly grease or line a rimmed sheet pan. Arrange sausages with direct pan contact — don't stack them on other ingredients — so heat reaches all sides evenly.

Preheat oven to 400°F and let it fully come to temperature. Arrange sausages on a rimmed sheet pan with space between each link — don't crowd them or they'll steam instead of brown. Roast on the center rack, uncovered, for 18–25 minutes. Flip each sausage with tongs at the halfway point (9–12 minutes in) for even browning. Thinner or pre-cooked links are done closer to 18 minutes; thicker raw sausages may need the full 25. Look for a golden-brown casing with light blistering, but always confirm doneness with a thermometer — color alone isn't reliable.

Use an instant-read thermometer inserted into the center of the thickest sausage — you're looking for 160°F. No pink interior, juices run clear. Not there yet? Return to the oven and check every 3 to 5 minutes. Rest on the pan for 2 to 3 minutes before cutting. Skipping this step causes juices to run out and leads to dry sausage. Serve hot. Reheat leftovers in a 350°F oven — avoid the microwave, which makes the casing rubbery.