TO PREPARE

1. Heat the oven to 425°F. Set a large rimmed baking sheet on the counter.
2. Add the cherry tomatoes, sliced peppers, red onion wedges, and smashed garlic to the sheet pan. Drizzle with olive oil, then season with salt and black pepper. Toss to coat and spread into an even layer.
3. Nestle the sausages among the vegetables, spacing everything out so it roasts instead of steaming.
4. Roast for 15 minutes, then flip the sausages and stir the vegetables. Return to the oven and roast until the sausages are browned and cooked through and the tomatoes are blistered, about 10 to 15 minutes more.
5. If you want a little extra punch, whisk mustard with red wine vinegar or lemon juice, then drizzle over the hot pan.
6. Finish with chopped herbs. Serve straight from the pan, or plate with crusty bread, mash, or a simple salad.