1️⃣ Prepare the cookies:
In a large mixing bowl, cream the butter and sugar until light and fluffy. Beat in the egg and vanilla extract. Gradually add the flour, baking powder, and salt, mixing until a soft dough forms.

2️⃣ Chill the dough:
Wrap the dough in plastic wrap and refrigerate for at least 30 minutes to make it easier to handle.

3️⃣ Shape and bake:
Preheat the oven to 350°F (175°C) and line baking sheets with parchment paper. Roll the chilled dough into 1-inch balls and place them 2 inches apart on the baking sheets. Flatten slightly with your hand or the bottom of a glass. Bake for 10-12 minutes, or until the edges are lightly golden. Cool completely on wire racks.

4️⃣ Make the ganache:
Heat the heavy cream in a small saucepan until it just begins to simmer. Pour the hot cream over the chopped chocolate in a bowl. Let sit for 2 minutes, then whisk until smooth and glossy.

5️⃣ Assemble the cookies:
Spoon or pipe a dollop of ganache onto the center of each cooled cookie. Immediately add festive sprinkles or edible glitter while the ganache is still soft.

6️⃣ Set and serve:
Allow the ganache to set at room temperature or in the refrigerator for 15-20 minutes. Serve and enjoy these elegant holiday treats!