Preheat your oven to 325 degrees. Line your baking sheets with parchment paper. 

Using your hand mixer, beat your butter until it is light and fluffy. Next add your egg yolk, powdered sugar, vanilla and salt. Mix after each new addition.

Add your gluten free flour. Rather than using your hand mixer to mix this, it is much better to wash your hands (or wear gloves) and mix the cookie dough with your hands. The dough is dry. Just keeping mixing it all together. 

Using a tablespoon or cookie scoop, take 1 tablespoon of cookie dough and roll into a ball with your hands. Next roll in the granulated sugar, making sure to cover all sides with sugar. Place on your baking sheet and press your finger in the center to make a little well. Add your favorite seedless jam to each well.

Place your baking sheet in the oven and bake for 12-13 minutes. Remove from the oven and allow to cool on the baking sheet for about 10 minutes before moving to a wire rack to cool longer.