In a stand up mixer or large bowl, cream the butter, peanut butter and the sugars until they are light and fluffy. Make sure the sugar is disolved.
Next beat in the eggs and vanilla. In a separate bowl combine the flour, baking soda and salt and gradually add to the creamed mixture and mix well.
Stir in the chocolate chips and the peanut butter cups (I cut mine in half but next time will not).
I chilled mine overnight but chill at least one hour. Bake at 350° and drop by the rounded teaspoons on parchment paper on a cookie sheet until edges are lightly brown about 10 minutes. Cool for a few moments and then remove to the wire rack.
Note: I always do a test run before I bake all my cookies this way I can make sure the oven temp is right and so is the baking time for my oven. I will bake only 1 cookie first. That way if I don't have the timing right for my particular oven, I will only lose 1 cookie and not an entire sheet of them.