My guess - just make little brownies (use small scoop). Right after they come out press with tart shaper and then put reeses inside. I filled mine with homemade 2-step fudge in easy decorator. Yum.

 

brownies

Here is the recipe you requested: Brownie Peanut Butter Cups

1- package ofbrownie mix( 15- ounces)
1/3-cup hot water
1/4-cup oil
1- egg
48- minature chocolate covered peanut butter cups


Preheat oven to 350.Combine brownie mix,water,oil and egg. Beat with a spoon. Fill paper lined mini- muffin cups about 1/2 full. Press one peanut butter cup into batter in each cup. Bake 15-20 minutes or until brownie is set. Cool completly. Yield: 40 -48 pieces