Grease a 9x9 inch square pan with butter or use baking spray.
Mix together the flour, salt, and baking soda.
In a bowl of electric mixer, beat butter, peanut butter, and sugars until smooth, about 3 minutes. Add in vanilla and egg. Mix to combine.
Add in dry ingredients and mix until combined.
Spread evenly into pan and bake for 20 - 25 minutes or until golden and set.
Let cool on wire rack.
Make Ganache topping:
Combine the chocolate chips and heavy cream in a microwave safe bowl and cook in the microwave for 30 seconds. Stir with a fork as it acts as a mini whisk. Continue heating at 15-30 second intervals, stirring until chocolate is smooth and melted.Alternatively, place the chocolate chips in a small bowl. Heat the cream in a small saucepan until the edges start to bubble. Pour the hot cream on top of the chocolate chips and stir until melted.
Pour ganache evenly over the bars. Spread evenly over the top or tilt pan to let it run to sides and corners. Place the pan in the fridge or freezer until the chocolate is set. Once cooled, cut into squares. You can cut larger bars which will yield you 16 or smaller bars of 24.
Top with your choice of toppings or serve plain.
Notes
Notes 1: I don't recommend natural peanut butter here.Notes 2: If you have peanut butter whiskey, you can use it here. It gives a very nice flavor to these bars. I have a bottle on-hand to use for all my peanut butter recipes.