Tater Tot Casserole

Name: Tater Tot Casserole
Ingredients: 3 tablespoons extra-virgin olive oil; 1/2 cup finely chopped onion; Two 10-ounce packages frozen chopped spinach, thawed and squeezed dry; 3 garlic cloves, minced; 1 cup whole milk; 1 cup heavy cream; 1/2 teaspoon freshly grated nutmeg; 1/2 cup freshly grated Parmigiano-Reggiano cheese; 1/2 cup grated Gruyère cheese; Kosher salt; Pepper; 3 large eggs, beaten; 1 pound pork sausage; 2 pounds frozen Tater Tots; Canola oil cooking spray