Step 1: In a large bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and 1/2 teaspoon salt.
Step 2: In a separate medium bowl, whisk together the milk, eggs, and melted butter or oil until smooth.
Step 3: Pour the wet ingredients into the dry ingredients. Stir gently until just combined. A few lumps are fine. Let the batter rest for 5-10 minutes.
Step 4: In a large skillet over medium heat, cook the ground breakfast sausage, breaking it up with a spoon, until browned and no longer pink. Drain any excess grease. Season the cooked sausage with smoked paprika, salt, and black pepper to taste.
Step 5: Preheat your oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish.
Step 6: Spread half of the cooked sausage evenly across the bottom of the prepared baking dish. Sprinkle with half of the shredded cheddar cheese and half of the chopped green onions.
Step 7: Carefully pour the pancake batter evenly over the sausage and cheese layer.
Step 8: Top the batter with the remaining cooked sausage, cheddar cheese, and green onions.
Step 9: Bake for 30-35 minutes, or until the casserole is golden brown and puffed, and a toothpick inserted into the center comes out clean. If the top starts to brown too quickly, you can loosely tent it with aluminum foil for the last 5-10 minutes.
Step 10: Remove from the oven and let rest for 5-10 minutes before slicing and serving. Drizzle with maple syrup if desired.