Preheat the oven to 350º. Cream the butter, peanut butter and the sugars, then mix in the eggs and vanilla until well blended. Add the flour and baking soda. Roll dough into 1” balls . Place balls on cookie sheets lined with parchment paper, and bake about 7-8 minutes (don’t overbake!). Cool. Match pairs of cookies so they fit, then spread the flat side of one with jelly and press the flat side of the other cookie to form a sandwich.