Preheat oven to 350 and prepare a 9x13 pan. No need to grease.
Spread brownie cubes evenly in the bottom of the pan
Drizzle the brownies with your melted butter and the chocolate chips.
Whisk together the sugar, milk, eggies, vanilla, and instant espresso powder if using. You can also use chocolate milk for this if you're an insane chocolate freak like me and nobody can stop you.
Pour the milk mixture over the brownie cubes, taking care to make sure the pieces are all mostly submerged. You can press lightly with a spatula or a fork to ensure this if needed.
Bake 40-50 minutes until the custard is set on top, it springs back against your fingertip when you lightly poke it, and then prepare the fucking vanilla ice cream even though you are NOT ready for this.
