01 -
Set oven temperature to 350°F (175°C) and line a baking sheet with parchment paper.
02 -
In a mixing bowl, beat together unsalted butter, granulated sugar, and brown sugar until the mixture is light and fluffy, about 3 minutes.
03 -
Add egg yolk and vanilla extract to the creamed mixture and blend until smooth and well combined.
04 -
Gradually fold in the all-purpose flour until just combined, taking care not to overmix.
05 -
Scoop dough into approximately 1 inch diameter balls and arrange them evenly spaced on the prepared baking sheet.
06 -
Use your thumb or a small spoon to press a shallow well into the center of each dough ball.
07 -
Fill each indent with the chosen jam or chocolate filling.
08 -
Bake for 12 to 15 minutes until the edges appear lightly golden while the centers remain soft.
09 -
Allow cookies to cool on the baking sheet briefly before transferring to a wire rack to cool completely.