In a large mixing bowl, cream together softened butter and granulated sugar until light and fluffy, about 3–5 minutes. Add in egg yolk and vanilla extract, mixing well.

Gradually incorporate the sifted dry ingredients until just combined, avoiding overmixing.

Divide the dough into two equal portions and flatten each into a rectangle about 1-inch thick. Wrap and refrigerate for at least 45 minutes.

Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

On a lightly floured surface, roll out one portion of dough to about 1/4 inch thick. Cut out shapes with cookie cutters, half with center cut-out.

Bake for 9-10 minutes, allowing edges to look slightly crisp and centers remain tender. Cool on pan for 15 minutes before transferring to a wire rack.

Dust cookies with cutouts lightly with powdered sugar, spread Nutella on each uncut cookie, and sandwich them together.