Preheat the oven to 325°F conventional (no fan) and line one baking sheet with parchment paper. I do not recommend using the convection setting for these cookies.

In the bowl of a stand mixer fitted with the paddle attachment, add all the ingredients. (Butter, powdered sugar, all-purpose flour, kosher salt, and vanilla extract.) Mix on medium-low speed until a smooth dough forms.

Pinch off pieces of dough about an inch across. Roll into a ball and then roll in granulated sugar. You will have approximately 15 cookies.

Place on parchment lined baking sheet about an inch apart, offset slightly. Press your thumb or forefinger into the center of each cookie gently, making an indentation. It should go about halfway into the cookie. Fill with jam before baking, but bake unfilled for a chocolate filling.

Bake in preheated oven for 12-15 minutes or until the surface looks matte and no longer glossy. I rotated my trays after 6 minutes.

Cool completely on a wire rack.