Preheat the oven to 350°F. Line a 9×13-inch pan with parchment paper, leaving an overhang. Set aside.

In a medium bowl, whisk together the flour, salt, and cocoa powder.

In a small saucepan over low heat, melt the chopped unsweetened chocolate and cubed butter, stirring occasionally for about 5 minutes.

In a stand mixer or with a hand mixer, beat the sugar and eggs for 60 seconds until pale yellow and doubled in volume.

Gradually pour the melted chocolate into the egg mixture while mixing on low speed. Add the vegetable oil and vanilla extract, continuing to mix on low.

Slowly add the dry ingredients to the wet mixture, mixing until fully combined.

Pour the batter into the prepared pan.

Bake for 25-35 minutes. Allow the brownies to cool completely.

In a medium bowl, combine the creamy peanut butter, softened butter, and vanilla extract. Beat with an electric mixer on medium speed until smooth and well combined.

Gradually add the powdered sugar, beating on low speed at first (to avoid a sugar cloud!), then increasing to medium speed. Mix until the mixture becomes thick and a bit crumbly.

If the mixture feels too stiff or dry, beat in 1 tablespoon of heavy cream to soften it up. The final texture should be thick but spreadable.

Once your brownies are baked and completely cooled, spread the peanut butter layer evenly over the top.

Place the chocolate chips in a medium heat-proof bowl.

In a small pot over low heat, heat the heavy cream to a gentle simmer – this is just before a rapid boil.

Pour the heavy cream over the chocolate chips. Allow the mixture to stand for 1-2 minutes. Then use a spatula to stir the mixture until smooth.

Spread the ganache evenly over the peanut butter layer.

Refrigerate the brownies for at least 1 hour, or until set, before slicing and serving.

Note: for clean cuts, wipe the knife clean between each use.