Preheat oven to 350 degrees. In a mixing bowl whisk together flour, baking soda and salt for 20 seconds, set aside.
In the bowl of an electric stand mixer fitted with the paddle attachment blend together butter, granulated sugar and brown sugar just until creamy.
Mix in peanut butter and blend just until combined. Mix in egg and vanilla. With mixer set on low speed slowly adding in flour mixture and mix just until combined.
Scoop dough out 1 Tbsp at a time and roll into balls. Place on baking sheets lined with parchment paper or silicone liners, spacing cookies two inches apart. Make an indentation with the back of a rounded 1/2 tsp in the top of each cookie*.
Bake in preheated oven 10 - 13 minutes (for softer cookies bake near lesser time for crisper bake more near greater time).
Remove from oven make a indentation in center of cookies with the back of a rounded tablespoon (they likely flattened out so they just need one more indentation). Cool on baking sheet several minutes then transfer to a wire rack to cool completely.
Once cool spoon and spread 1 tsp jam into center of each cookie. Store in an airtight container in a single layer.
*For thicker cookies don't add indentation needed until after baking, just leave as whole rounds without indentation in them before baking. Then once they've baked, remove from oven and immediately make indentation by using the bottom of a rounded teaspoon to gently press to create well in center. Then proceed as directed.