In a mixing bowl, cream butter, peanut butter and sugars; add egg and vanilla; stir together flour, baking soda and salt; add to creamed mixture. Mix well.
Chill for 1 hour.
Shape into 48 balls.
Place in lightly greased mini-muffin tin.
Bake at 325 F degrees for 14-16 minutes or until lightly browned.
Remove from oven and immediately make wells in the center of each by lightly pressing with a melon baller.
Cool in pans for 5 minutes.
Then carefully move to wire racks.
Melt chocolate chips in a double boiler over simmering water.
Stir in milk and vanilla; mix well.
Using a small pitcher or pastry bag, fill each shell with filling. Sprinkle with peanuts. (Leftover filling can be stored in the refrigerator and served warm over ice cream, there won't be any left usually)