Preheat oven to 350 degrees
Prepare a large baking sheet by lining it with parchment paper
Chop the peanuts in a food processor or with a sharp knife until they are in smaller pieces
Combine the flour, baking soda, baking powder, and salt in a medium-sized bowlWhisk together to combine.
Combine the cooled melted butter, the brown sugar and the white sugar in a large bowl, mix until smooth on medium speed a hand mixer.
Add the eggs, vanilla and peanut butter to the butter/sugar mixture and beat until smooth.
Stir the flour mixture into the butter/sugar mixture in two steps just until combined.
Stir in the chopped peanuts until combined
Refrigerate the dough in the bowl for at least 10 minutes and up to 6 hours to firm up before baking.
Scoop a heaping tablespoon of cookie dough and roll it into a ball with your hands, then place it on the cookie sheet, placing each cookie at least 3 inches apart from each other.
Bake the cookies until very lightly colored, about 15 minutes.
Remove from oven and while the cookies are warm, use the back of a spoon to gently make a small indentation in the middle of each cookie. This is where the jam will go later.
Cool the cookies completely, then add about one teaspoon of jam into each indentation.