Preheat the oven to 375 degrees F (190 degrees C).
Heat the olive oil in a large skillet over medium heat. Add the onion and garlic and cook until softened, about 5 minutes. Add the Brussels sprouts and potatoes and cook, stirring occasionally, until the vegetables are lightly browned, about 10 minutes.
Add the thyme, salt, and pepper and cook for 1 minute. Add the broth and bring to a simmer. Simmer for 5 minutes. Stir in the milk and bring to a simmer again. Remove from the heat.
Pour the vegetable mixture into a 9-inch square baking dish. Sprinkle the Parmesan cheese and breadcrumbs on top. Bake for 30 minutes, or until the top is golden brown and the vegetables are tender.
Interesting Facts
Brussels sprouts are an excellent source of fiber, vitamins, minerals, and antioxidants.
Potatoes are a great source of potassium, vitamin C, and B vitamins.
This casserole is a great way to get your daily servings of vegetables.