Combine the cold butter, grated cheese, flour, egg, salt, and cayenne in a food processor. Pulse just until the mixture resembles coarse meal. Be careful not to overprocess. Alternatively, use a pastry blender or two knives to cut the butter into the dry .
Gather the dough into a ball, wrap it in plastic, and refrigerate for at least 15 minutes or until you're ready to bake.
Preheat the oven to 400°F / 200°C.
Line a baking sheet with parchment paper or use a nonstick sheet.
Form the chilled dough into 1-inch balls and place them 2 inches apart on the prepared baking sheet. Gently flatten each ball with your fingers or the bottom of a glass.
Bake for 10-12 minutes, or until the shortbreads are puffed and golden brown.
Let the shortbreads cool completely on a wire rack.
Once cool, sprinkle with paprika, if using, and serve.
Don't Overwork the Dough: Pulse the just until they form a coarse meal. Overmixing develops gluten and results in tough, not tender, shortbread.
Chill Out: Don't skip refrigerating the dough.
Chilling solidifies the butter, which helps the puffs hold their shape and creates that perfect melt-in-your-mouth texture.
