Preheat the oven to 350°F. Spray an 9×13-inch baking pan with cooking spray or line with parchment paper

On medium speed in a stand mixer or with a hand mixer, cream the butter, peanut butter and sugars for 2 minutes until fluffy

Add in the eggs and vanilla extract and mix on medium for 1 more minute

Add in the flour and salt and mix on low until just combined (~20 seconds)

Pour the batter into the prepared pan and smooth with a spatula to form an even layer

Bake for 25-30 minutes until the center is no longer jiggly but soft (note this bake time is for a 9×13 inch metal pan – if using a glass pan or smaller pan, the time will need to be increased)

After baking, let them cool to room temperature before topping with the ganache

To make the ganache, add chocolate, butter, salt, and vanilla into a bowl. Set aside

In a small pan over medium heat, heat cream and sugar until hot but just before boiling

Pour the ganache over the cooled cookie bars. Place in the fridge until the topping is just set (so that the bars can be cut but is not hard)

Cut and top with flaky sea salt