Line 2 baking sheets with parchment paper.

In the bowl of a stand mixer fitted with the paddle attachment, beat ½ cup (146 grams) hazelnut-chocolate spread and butter at medium speed until smooth and combined. Add granulated sugar and brown sugar; beat at medium-high speed until light and fluffy, 2 to 3 minutes, stopping to scrape sides of bowl. Beat in egg and vanilla until combined, stopping to scrape sides of bowl.

In a medium bowl, whisk together flour, baking powder, and salt. Add flour mixture to butter mixture, and beat at low speed just until combined. Fold in hazelnuts. Using a 1/-tablespoon spring-loaded scoop, scoop dough (about 30 grams each), and roll into balls. Flatten dough balls into 2/-inch rounds. Spoon 1 heaping teaspoon (about 6 grams) hazelnut-chocolate spread into center of half of dough rounds (you’ll have leftover spread). Cover with remaining dough rounds, and gently crimp edges to seal. Place 2 1/2 inches apart on prepared pans. Refrigerate for at least 30 minutes.

Gently shape dough to be about 2 inches in diameter, smoothing edges.

Bake until lightly puffed, tops look dry, and edges are set, 13 to 16 minutes. Let cool completely on pans on wire racks. Garnish with confectioners’ sugar, if desired.

Store in an airtight container for up to 4 days.