Preheat your oven to 350°F and line two baking sheets with parchment paper.
In a large bowl, cream together the softened butter and sugar until light and fluffy, about 3 minutes.
Beat in the egg yolks, vanilla extract, and almond extract until well combined.
In a separate bowl, whisk together the flour and salt. Gradually add to the butter mixture, mixing just until combined.
Roll the dough into 1-inch balls and place them 2 inches apart on the prepared baking sheets.
Use your thumb (or the back of a small spoon) to make an indentation in the center of each cookie. Don't press all the way through!
Fill each indentation with about ½ teaspoon of jam.
Bake for 12-14 minutes, until the edges are just starting to turn golden. The centers should still look pale.
Cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely. Dust with powdered sugar if desired.