In a large skillet over medium heat, cook sausage until browned and crumbly, about 5-7 minutes. Remove sausage, reserving drippings. Melt butter and whisk in flour to create a roux. Gradually pour in milk while whisking continuously until gravy thickens and becomes creamy, about 3-5 minutes. Stir the cooked sausage back into the gravy and set aside.

In a mixing bowl, crack and beat eggs until well combined. Add cheese and additional fillings such as sautéed veggies or hash browns. Season with salt and black pepper.

Preheat oven to 350°F. Spoon egg mixture onto tortilla center, roll up, and place seam-side down in a baking dish. Repeat with remaining tortillas and filling.

Pour sausage gravy over the assembled enchiladas. Bake uncovered for 25-30 minutes or until edges bubble and top is golden brown.

Let sit for 5 minutes before slicing. Serve warm, garnished with additional cheese or fresh herbs.