Preheat your oven to 350° F. Line two baking sheets with parchment paper or silicone baking mats.

In a large mixing bowl, cream the butter with an electric mixer until nice and creamy.

Add the peanut butter and mix until it's just combined with the butter.

Add the granulated and brown sugars, and mix until well creamed together with the butters.

Add the egg and vanilla and mix until just combined.

Add the baking powder, salt, and flour and mix, scraping the sides of the bowl as needed, just until the last streaks of flour disappear into the dough.

Roll the dough into balls about 1 ½ tablespoons (38 to 40 grams) in size.

Roll each ball in granulated sugar and place onto the prepared baking sheets about 2 inches apart.

Use a fork to lightly press the traditional crisscross design into the cookies.

Use your thumb to gently press an indent into the center of each cookie on top of the crisscross, and spoon in about 1 teaspoon of preserves into the center of each cookie.

Bake the cookies for 8 to 9 minutes. The edges will appear just set.

Let cookies cool about 5 minutes on the baking sheet, then transfer to a cooling rack to cool completely.

Store leftovers in an airtight container at room temperature for up to 5 days or 7 days in the fridge.

The cookies can be made, fully assembled (with the jam in the centers) and refrigerated on the baking pan for 24 hours before baking.