Preheat oven to 350°F and line two baking sheets with parchment paper.
Make the Cookie: In a large bowl, beat at medium speed sugar, butter, egg, and vanilla until creamy.
Lower speed and add in flour and baking powder, beating until combined.
Chill for 1 hour, to prevent dough from spreading too much when baked (if you’re on a time crunch and this step took you by surprise, you should be ok to bake the cookies – just space them a little further apart.)
Roll dough into 1 1/4-inch balls, placing the balls 2 inches apart on the cookie sheet.
Using your thumb, make an indentation in the center of each cookie, rotating your thumb to deepen and widen the indentation slightly.
Make the Filling: Combine all filling ingredients in a bowl, mixing well.
Fill each cookie – indentation with 1 teaspoon of filling. I made all the cookies at once (using parchment paper on the counter for those that didn’t fit on my cookie sheet) so that if there was extra filling, I could spread it around.
Bake for 8-12 minutes, until lightly browned.
Let sit on cookie sheets for a minute or two before transferring to a cooling rack.
Freeze for up to 3 months in an airtight container, with wax paper between layers.
Nutrition Info (per cookie): 130 calories; 7 g. fat; 1 g. protein; 15 g. Carbs; less than 1 g. fiber.