Preheat oven to 325 degrees Fahrenheit.
Liberally spray a large (13″ x 19″) baking sheet with nonstick spray.
Whisk the eggs, half-and-half, salt, and pepper in a separate bowl.
Pour the eggs onto the baking sheet and sprinkle on the scallions.
Carefully transfer the baking sheet to the oven.
Cook for 15 – 18 minutes or until the eggs are set.
While the eggs cook, warm the sausage according to the package directions.
When the eggs are set, remove the pan from the oven and cool for 5 minutes.
Use a biscuit cutter or mason jar lid to make egg circles. I like the egg to fill the whole sandwich.
Assemble the sandwiches in this order: muffin or bagel bottom > cheese > sausage > egg > cheese pieces > muffin or bagel top
Heat immediately or store using one of the methods below.
To enjoy right away, pop it in the microwave for 60 seconds or toast it in the oven at 350ºF until the cheese is melted.