Let the butter sit on the counter for a few hours until soft. Line baking sheets with parchment paper or silicone liners - or spray with cooking spray. Preheat your oven to 350 degrees.
In a large mixing bowl, beat the butter and peanut butter together at medium speed until creamy. Add the brown sugar and white sugar and beat for another minute or two.
Beat in the eggs and vanilla, scraping the sides of the bowl with a spatula.
Add the flour, baking powder, soda, and salt. Stir until there are no streaks of flour.
Roll dough into balls about 2 inches across. (Mine weighed 1.5 ounces.) Roll in sugar.
Use a small measuring cup or your fingers to press a large, flat well in the middle of each cookie dough ball. Place the flattened cookie dough balls at least 2 inches apart on a prepared baking sheet.
Fill the center of each cookie with about 2 teaspoons of jam.
Bake at 350° for about 12-14 minutes, or until cookies are set and golden brown on the bottom. Add another teaspoon of jam to each cookie.
Let the cookies cool on the cookie sheet for 10 minutes, then transfer to a wire rack to cool completely.