Preheat the oven to 400°F. In a small bowl, stir together the butter, lemon zest, lemon juice and garlic.
On a large baking sheet, arrange the carrots, radishes, bell pepper, and eggplant in an even layer. Drizzle about half of the lemon garlic butter over the vegetables and toss well to combine. Season with salt and pepper.
Roast until the veggies are just tender, 15 to 17 minutes. Add the tomatoes, asparagus, zucchini and sausage. Drizzle the remaining lemon garlic butter over the mixture, and toss well to combine.
Roast until all the vegetables are very tender and the sausage has begun to brown, 17 to 20 minutes.