In a large bowl, whisk flour, sugar, cocoa powder, baking powder, baking soda, and salt together.
In a medium bowl, beat eggs, milk, oil, and vanilla together.
Add boiling water, stir until combined.
Pour wet ingredients into dry ingredients and mix on medium speed until combined.
Pour into prepared baking dish and bake for 35-40 minutes or until toothpick inserted in center comes out clean.
Remove from oven and let cool completely.
Carefully grab both sides of foil and gently pick up cake and place on a hard surface.
Slice cake in half lengthwise.
Carefully remove top layer and then place foil and bottom layer back into the baking dish.
Once cake has cooled completely, remove ice cream from freezer and add ice cream on top of cake. To make it easier, cut cardboard of ice cream contained and then slice ice cream about ¾ - 1 inch thick.
Place ice cream evenly over cake and if needed, piece the ice cream in bare spots so the whole cake is covered.
Next, add top layer of cake on top of ice cream.
Cover with plastic wrap and place in the freezer until ready to serve.