Prepare the Dough:

1. In a large mixing bowl, blend softened butter and granulated sugar until the mixture becomes light and airy.
2. Add the eggs one at a time, ensuring each is fully incorporated before stirring in the vanilla extract.
3. In a separate bowl, whisk together the flour, baking powder, and a pinch of salt.
4. Slowly fold the dry ingredients into the butter mixture, mixing just until a smooth dough forms.
5. Divide the dough into two equal portions, wrap each in plastic wrap, and refrigerate for at least 30 minutes to firm up.

Make the Nut Filling:

1. In a bowl, mix finely ground walnuts with granulated sugar, powdered sugar, cinnamon, and nutmeg until well combined.

Assemble and Bake:

1. Preheat the oven to 350°F (175°C).
2. On a lightly floured surface, roll out one portion of the chilled dough to ¼-inch thickness.
3. Evenly spread the nut filling over the dough, leaving a slight border along the edges.
4. Carefully roll the dough into a log, jelly-roll style, ensuring it stays tight to prevent air gaps.
5. Slice the roll into 1-inch pieces using a sharp knife.
6. Arrange the slices on a parchment-lined baking sheet, spacing them slightly apart.
7. Bake for 12–15 minutes or until the edges turn a light golden brown.
8. Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.