Preheat the oven to 400 degrees.
Mix the first eight ingredients in a medium-sized bowl.
Spread approximately one tablespoon of the Parmesan mixture evenly onto the cocktail bread and place on a baking sheet.
Bake in a preheated oven for 20 minutes or until the Parmesan Onion Appetizer Squares are golden in color.
Remove and serve hot, warm, or at room temperature.