Cut bread slices into 40 rounds, using a 3" biscuit cutter. Roll each bread round lightly with a rolling pin. Brush both sides of each round lightly with melted butter. Press into miniature (1 3/4") muffin pans lightly coated with cooking spray. Bake at 350° for 20 minutes or until crisp and golden.
Cook sausage, celery, and onion in a skillet over medium-high heat until sausage is browned, stirring until sausage is finely crumbled; drain.
Combine sausage mixture, eggs, and next 6 ingredients in a medium bowl; stir well. Spoon into prepared toast cups, filling three-fourths full.
Bake at 350° for 15 minutes or until set. Serve warm. Garnish, if desired.