Preheat the oven to 350°

Line an 8x8 inch square pan with parchment paper and spray that with cooking spray. This is for easy removal.

Stir together the flour, cocoa, and salt in a small bowl. Set aside.

In a heat-proof measuring cup or bowl, melt the butter in the microwave or in a small saucepan on the stove.

Stir in the chopped chocolate and heat briefly in 15 second intervals or gently on the stove until the chocolate has just melted. Be grateful not to overheat the mixture, as it will scorch.

In a stand mixer or a big bowl with a whisk, beat the egg yolks and the sugar until very light.

Add the butter-chocolate mixture and beat to combine.

Stir in the flour mixture, beating until just combined.

Beat in the heavy cream.

Using a spatula or large spoon, fold in the marshmallow crème, mixing just enough for there to be no large streaks. It is ok to have some streaking of the marshmallow crème left.

Spread the batter evenly into the prepared pan.

Bake for 35-45 minutes until a knife inserted in the center comes out clean. However, it should still be gooey.

Let cool completely.

Chop the cooled brownie into ½ inch pieces and place it into a freezer bag. The brownies will still be very gooey and stick together. break them up as much as possible.

Freeze until you are in need of brownie bites. The brownies can be further broken up when they are frozen, though they will still be gooey.