Classic Peanut Butter Cookie Bites with Chocolate and Crunchy Toppings - cookrisp

Ingredients

• 1 cup unsalted butter, softened
• 3/4 cup packed brown sugar
• 1/2 cup granulated sugar
• 1 large egg (optional)
• 1 teaspoon vanilla extract
• 2 cups all-purpose flour
• 1/2 cup creamy peanut butter
• 1/4 cup powdered sugar
• 1 1/2 cups semi-sweet chocolate chips
• 1/4 cup crushed Reese's Pieces, chopped peanuts, or mini M&Ms (optional)
• 1 egg yolk mixed with 1 tablespoon water, for brushing