• Place softened butter and powdered sugar in the bowl of a standing mixer with a paddle attachment. Mix at a low speed for 2 to 4 minutes, or until the butter mixture is pale yellow, light, and fluffy.
• Add vanilla and mix just until combined. *Scrape the bowl and paddle down two or three times with a spatula during mixing to ensure all the butter bits are mixed in.
• Add egg and about half of the flour with the motor running and beat until fully incorporated. Add the rest of the flour, cocoa powder, and salt, and mix until a dough forms. If the dough is too sticky, add a teaspoon of cocoa powder. If it is too dry, add a little water or milk (a teaspoon at a time).
• Wrap the dough in plastic wrap and transfer it to the refrigerator for 1-2 hours.
• Preheat the oven to 350°F/180°C.
• On a lightly floured surface, roll the dough to a ¼-inch (½ cm) thickness and cut circles using a cookie cutter.
• Place a flat teaspoon of the filling in the center of each circle. Pinch the edges together in three places so that they meet in the middle to form a triangular cookie shape. Fasten and arrange on a baking sheet lined with parchment paper. Don’t put in too much filling, or you won’t be able to close the Hamantaschen. You do not want the filling to come out.
• Place the baking sheet with the Hamantaschen in the freezer for 30 minutes before baking.
• Bake for 15-20 minutes until the dough is slightly golden at the bottom. Let it cool.

Optional- drizzle melted white chocolate on top