Preheat oven to 400°F. Grease a large rimmed sheet pan with olive oil.
Chop all of the veggies, doing your best to make them all even in size for even cooking. Place them on the sheet pan and add the sausage.
1 yellow squash, 2 zucchini, 1 small red onion, 8 oz mushrooms, 1 red bell pepper, 4 cloves garlic, 1 (12-oz) package smoked sausage
In a separate medium bowl, combine Italian seasoning, salt, pepper, and olive oil and stir to combine. Pour the herb mixture over veggies and toss to coat the veggies.
2 Tablespoons Italian seasoning, 1 teaspoon kosher salt, Black pepper to taste, 4 Tablespoons olive oil
Bake in the preheated oven for 25-35 minutes, stirring halfway through, until the veggies are tender and the sausage is golden brown. You can broil them at the end for 2-3 minutes if desired.
Serve in a bowl with or without brown rice.