In a 12-inch nonstick skillet, cook sausage, mushrooms, sweet pepper and green onions until meat is brown and vegetables are tender, stirring to break up sausage as it cooks. Remove sausage mixture from skillet; drain. In a small bowl combine sausage mixture and cheese; set aside. Carefully wipe skillet clean with paper towels; set aside.
With a 2-inch round cookie cutter, biscuit cutter or a small juice glass, cut out the center of each bread slice. (Use centers in another recipe for bread crumbs.) Spread both sides of the bread slices with the butter.
In the same 12-inch skillet, toast bread on one side over medium heat about 2 minutes or until golden brown. Reduce heat to medium-low. Turn the bread slices over.
Break one of the eggs into a 1-cup glass measuring cup with a handle. Holding the lip of the cup as close to the bread as possible, carefully slide egg into the hole. Repeat with remaining 3 eggs and bread slices. Lightly sprinkle the eggs with salt and ground pepper. Spoon sausage mixture atop bread slices, avoiding the egg as much as possible.
Cook, covered, for 10 to 15 minutes or until eggs are firm. Using a wide spatula, carefully lift out bread-and-egg slices and transfer to 4 dinner plates. Serve with assorted fresh fruit, if you like. Makes 4 main-dish servings.