Cook the Sausage: In a large skillet, cook the breakfast sausage over medium heat until browned and fully cooked. Break it up into crumbles as it cooks. Drain any excess fat and set aside.

Prepare the Pancakes: If using frozen pancakes, heat them according to the package instructions. Once cooked, cut them into quarters. If making homemade pancakes, prepare them as usual and then cut into quarters.

Assemble the Casserole: Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish. Layer the bottom of the dish with a layer of pancake quarters, followed by a layer of cooked sausage. Repeat with another layer of pancakes and sausage. Sprinkle the shredded cheddar cheese and green onions (if using) over the top.

Make the Egg Mixture: In a large bowl, whisk together the eggs, milk, vanilla extract, salt, pepper, and maple syrup (if using). Pour the egg mixture evenly over the pancake and sausage layers.

Bake the Casserole: Cover the dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for another 10–15 minutes, until the casserole is set and the top is lightly golden.

Serve: Let the casserole cool for a few minutes before slicing and serving. Optionally, drizzle with extra maple syrup before serving.