01 - Preheat oven to 375°F (190°C) and lightly grease a baking dish.
02 - In a skillet over medium heat, cook breakfast sausage until thoroughly browned, breaking it up as it cooks.
03 - Sprinkle flour evenly over the cooked sausage and stir constantly for 1 minute. Gradually whisk in whole milk. Continue cooking, stirring often, until the gravy thickens, about 5–7 minutes. Season with salt, black pepper, and a pinch of cayenne if desired. Remove from heat and set aside.
04 - In a clean skillet, melt butter or heat oil over medium-low. Whisk eggs with 1/4 cup milk, salt, and black pepper. Pour into the pan and scramble gently until just set. Remove eggs from heat to avoid overcooking.
05 - Arrange flour tortillas on a flat surface. Divide scrambled eggs, crumbled cooked sausage, shredded cheddar cheese, and diced green onions evenly among the tortillas. Roll each tightly and place seam side down in the prepared baking dish.
06 - Pour sausage gravy evenly over the assembled enchiladas. If desired, sprinkle additional cheddar cheese on top.
07 - Bake uncovered for 20 minutes, or until enchiladas are heated through and the top is bubbly.
08 - Remove from oven and garnish with extra sliced green onions before serving.