In a mixing bowl, add beaten eggs, peppers, cheese, green onion, bacon, spinach, salt and pepper. Mix until combined.
Cut out the center of the bread slices, leaving only the crust.
Heat butter in a large nonstick pan. Place bread slices in pan and fill each piece with egg mixture. Cook about 3 minutes and flip. Cook an additional 3 minutes. Add cheese to 1 slice of bread. Top with remaining slice and place a lid over the pan to melt cheese. Remove from heat and serve.