Using a hard wooden spoon (or you can cheat and use a mixer) cream together the butter and sugars until smooth.
Add the eggs until well combined, then add in the peanut butter and vanilla until smooth andcreamy .
In a separate bowl, whisk together the flour, baking soda, and saltuntil well combined.
Add the flour mixture to the butter mixture and stir (or mix) until evenly mixed.
Cover the dough and chill for 2 to 3 hours. Preheat the oven to 300°F
. Turn the dough -reserving roughly a quarter of it - into two lightly greased 8 X 8 pansand then press down Reese's cups into the dough in even intervals. Crumble remaining dough on top of the mixture
Bake for 20-25 minutes, rotating the pan halfway through the bakingtime, or until the edges are set and the bars seem done. L
Let the bars coolcompletely before cutting and transferring to a cookie jar or other air tight,room temperature storage.