Preheat the oven to 350 F.
Add the butter and sugar to a large bowl and beat with an electric mixer for 1 minute, until fluffy.
Add the vanilla, almond extract, egg yolks, and salt to the bowl with the butter and sugar and beat for another 30 seconds, until just combined.
Then, add the flour 1/2 cup at a time, beating constantly, until the dough is fully formed.
Line two baking sheets with parchment paper, then roll the dough into one tablespoon-sized balls, make an indentation in each with a teaspoon, or your finger, and fill with jam.
Bake for 18-20 minutes, until the cookies brown around the outside, then let cool for at least 15 minutes before serving.