To make the brownie layers, line two greased 8x8 baking pans with parchment paper, and preheat the oven to 350 degrees.
In a large glass bowl, combine the butter and chopped chocolate, and heat for 1 minute on high heat in the microwave. Stir the chocolate into the melted butter to dissolve any solid pieces, and reheat at 15 second intervals as needed to finish melting. Add the sugar while the chocolate butter mixture is hot to dissolve the granules.
When the mixture has cooled a bit, add the two eggs, vanilla, salt, and finally the flour. The mixture will be thick and rich, but don't overmix.
Divide the batter between the two pans evenly. Bake on a middle rack for exactly 12 minutes (or until a toothpick inserted comes out clean). Cool the brownie layers in the freezer for about 15 minutes.
When the brownies have cooled, scoop the softened ice cream (I used oreo cookie, and Just Sprinkles) on top of what will be the bottom layer, to your desired thickness. Top with the other brownie layer, compacting gently with the empty brownie pan on top to make sure pressure is even. I continue to use the parchment paper beneath and on top to ensure things aren't sticking. Chill for 30 minutes.
Transfer the massive layered brownie sandwich to a cutting board, and cut into four slices each way, resulting in a total of 16 delicious nuggets! Top with melted hot fudge sauce (to come later), roll in sprinkles or mini chocolate chips - whatever you like. They are also insanely good as is...