A rich, fudgy brownie on top and a warm, silky chocolate pudding underneath. During baking, the batter rises into a brownie-like layer while the liquid transforms into a luscious pudding sauce below.
Use Dutch-processed cocoa powder for a deeper, less acidic chocolate flavor, or stick with regular unsweetened cocoa for a classic taste. Whole milk gives the batter richness, but 2% milk works well too. If you only have salted butter, reduce the added salt to a pinch. For a more intense chocolate experience, swap semisweet chips for dark chocolate chips or chopped dark chocolate. Make sure the brown sugar is fresh and soft so it sprinkles evenly over the batter. The hot water should be just off the boil, not lukewarm, to help create the pudding layer. Do not stir after adding the hot water. Store leftovers in an airtight container in the refrigerator for up to 3 days.