Preheat your oven to 350°F. Grease a 9x13-inch baking dish with cooking spray.
In a large mixing bowl, combine the pancake mix, milk, eggs, vanilla extract, cinnamon, and salt. Whisk until smooth.
Spread the cooked and crumbled sausage evenly across the bottom of the prepared baking dish.
Pour the pancake batter over the sausage, ensuring it covers evenly.
Sprinkle the shredded cheddar cheese on top of the batter.
Drizzle the maple syrup over the cheese.
Bake in the preheated oven for 25-30 minutes, or until the casserole is golden brown and a toothpick inserted in the center comes out clean.
Let the casserole cool for about 5 minutes before slicing into squares. Serve warm, drizzled with additional maple syrup if desired.