Kue Pohon Natal yang Mudah Dihiasi

Bahan-bahan (15 porsi)

• 1 1/2 sticks (12 tablespoons) salted butter, at room temperature
• 3/4 cup brown sugar
• 1 teaspoon vanilla bean powder, or 1 tablespoon vanilla extract
• 1 egg, at room temperature
• 2 cups all-purpose flour, plus an additional 2-4 tablespoons, if needed
• 1/4 teaspoon baking soda
• 1/2 teaspoon kosher salt
• 12 ounces milk or semi-sweet chocolate, melted
• 4 ounces white chocolate, melted
• assorted sprinkles, for decorating