Preheat the Oven and Prepare the Dish: Heat the oven to 375°F (190°C). Grease a 9 x 13-inch (23 x 33 cm) baking dish evenly with the softened 1 tablespoon (14 g) butter. This ensures the casserole won’t stick and will come out easily once baked.

Brown the Sausage: Heat a 12-inch (30 cm) skillet over medium heat. Add the breakfast sausage, along with the optional 1 teaspoon (5 ml) oil only if the sausage is very lean. Cook for 7 to 9 minutes, breaking it into small bite-size crumbles, until browned and fully cooked. Pork sausage should reach 160°F (71°C). Browning the sausage adds flavor and ensures it’s cooked through.

Drain the Sausage: Transfer the cooked sausage to a paper-towel-lined plate or drain away excess grease. Let it cool slightly while you prepare the batter. Removing excess fat helps prevent a greasy or heavy casserole, ensuring a better texture.

Mix the Dry Ingredients: In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt until evenly combined. This step is crucial for ensuring that the leavening agents are well distributed throughout the batter.

Mix the Wet Ingredients: In a medium bowl, whisk the eggs until blended. Add the buttermilk, 1/4 cup (60 ml) maple syrup, melted butter, and vanilla. Whisk until smooth. Combining these ingredients creates a rich and flavorful batter.

Make the Pancake Batter: Pour the wet mixture into the dry ingredients. Fold gently with a rubber spatula just until no large pockets of dry flour remain. A few small lumps are fine. The batter should be thick but pourable; overmixing can make the casserole dense. This gentle mixing helps maintain the light texture of the pancakes.

Assemble the Casserole: Spread about half of the pancake batter evenly in the prepared baking dish. Scatter the cooked sausage over the surface, then spoon and gently spread the remaining batter on top. Some sausage may remain visible, which is fine. This layering ensures that every bite has a good balance of pancake and sausage.

Bake Until Golden and Set: Bake at 375°F (190°C) for 30 to 35 minutes, or until the top is lightly golden and the center springs back when gently pressed. A toothpick inserted into a pancake-heavy section near the center should come out without wet batter. This step is essential for achieving a fluffy and fully cooked casserole.

Check the Center: If the edges are browned but the center still looks wet or jiggles like uncooked batter, continue baking for 3 to 5 minutes and check again. Avoid covering the dish unless the top is becoming too dark. This ensures that the casserole cooks evenly throughout.

Rest and Serve: Remove the casserole from the oven and let it rest for 5 minutes before slicing into 12 pieces. Serve warm with optional maple syrup. Resting allows the casserole to set, making it easier to cut and serve.