Preheat oven to 350 degrees. Grease a 9-by-13-inch pan and set aside.
In a bowl, cream together peanut butter, butter, brown sugar, sugar and vanilla with a mixer, until thoroughly mixed. Add eggs and combine well.
Combine flour and baking soda and add to butter mixture and blend. Stir in 3/4 cup mini chocolate chips. Spread batter evenly into prepared pan and bake in preheated oven for 20 to 25 minutes.
Remove from oven and sprinkle the reserved chocolate chips on top. When chips have melted, spread evenly over the top. Cool completely in the pan and cut into squares and place in mini tassie papers. Makes 36 bars. Enjoy!