Not specified

1. Pour sugar and salt into bowl of stand mixer and whisk.
2. Add butter to sugar and blend mixture using the paddle attachment until well creamed together.
3. Scrape down bowl.
4. Mix in egg yolks and vanilla extract, scrape down bowl.
5. Add flour and mix until combined.
6. Scoop dough out and shape into 1-inch (3cm) balls (just slightly over 1 Tbsp each, or 20g).
7. Place on a flat dish lined with parchment paper and make an indent in each cookie using thumb or a wine cork (just don't push all the way through the dough, but make large enough to fit 1/2 tsp of jam).
8. Freeze the shaped cookie doughs for 20 minutes.
9. Meanwhile preheat oven to 350 degrees.
10. Remove half of the shaped thumbprints and place on a parchment paper lined baking sheet spacing 2-inch (5cm) apart.
11. Fill with 1/2 tsp jam in each indent.
12. Bake in preheated oven 13 to 15 minutes until nearly set.
13. Let cool several minutes then transfer to a wire rack to cool completely.
14. Repeat with remaining cookie dough.
15. Store cookies in an airtight container at room temperature.

Not specified