Preheat your oven to 350°F and line two baking sheets with parchment paper.
In a large bowl, cream together the butter and granulated sugar until light and fluffy, about 3 minutes. Beat in the egg yolks, vanilla, and almond extract until well combined.
Mix in the flour and salt until just combined. Don't overmix or your cookies will be tough!
Roll the dough into 1-inch balls, then roll each ball in the sparkling sugar to coat generously. Place about 2 inches apart on your prepared baking sheets.
Using your thumb or the back of a 1/2 teaspoon measuring spoon, make a deep indent in the center of each cookie. If the edges crack, gently smooth them back together.
Fill each thumbprint with about 1/2 teaspoon of raspberry jam.
Bake for 12-14 minutes, until the edges are just starting to turn golden. The centers should still look slightly underdone—they'll firm up as they cool!
Let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
