Beat the softened butter and granulated sugar together for 2–3 minutes, until light and creamy. Add the egg yolks, vanilla extract, and optional almond extract, then mix until smooth.

Whisk the flour and fine salt together in a separate bowl. Add the dry ingredients gradually to the butter mixture, mixing only until a soft dough forms.

Cover the dough and refrigerate it for 30–60 minutes. Chilling makes the dough easier to shape and helps the cookies hold their form in the oven.

Heat the oven to 350°F (175°C) and line baking sheets with parchment paper. Portion the dough into balls using about 1 tablespoon per cookie.

If using the optional coating, roll each dough ball in lightly beaten egg white and then in finely chopped almonds or pecans. Arrange the balls about 2 inches apart on the prepared baking sheets.

Press a deep indentation into the center of every dough ball with your thumb or the rounded end of a wooden spoon. Fill each indentation with approximately 1/2 teaspoon of raspberry jam, taking care not to overfill.

Bake for 10–13 minutes, until the edges are set and just lightly golden while the centers remain fairly pale. Cool the cookies on the baking sheet for about 5 minutes, then transfer them to a wire rack.