Preheat oven to 350 degrees F. Line two cookie sheets with parchment paper.
In a large mixing bowl, add in the butter and peanut butter. Beat with a hand mixer on medium speed until combined.
Add in the granulated sugar, brown sugar, and vanilla extract. Beat until light and fluffy..
Add in the eggs and vanilla extract. Mix until incorporated.
Add in the flour, baking powder and salt. Mix until a dough ball forms. If you want the cookies to keep their shape a little better, at this point cover the dough with plastic wrap and refrigerate for 1 hour. Chilling isn't necessary for this recipe.
Scoop the cookies out using a 1 1/2 tablespoon cookie scoop. Roll the dough ball between your two palms until smooth.
Press down in the center of the dough using a measuring spoon, measuring cup, your finger, etc to form the thumbprint center.
Place each cookie ball onto the prepared cookie sheet about 1 inch apart.
Place a teaspoon (or more depending on how big of a thumbprint you made) of jam into the hole.
Place into the preheated oven and bake for 12 - 14 or until done. Place on a cooling rack to cool. If you need the jam to spread out more, gently spread out with a toothpick.
Notes
To store any leftover peanut butter jam thumbprint cookies, place in an air tight container at room temperature for up to 2 to 3 days or in the refrigerator for up to a week..