Preheat oven to 325° F. Butter a 2-quart baking dish.
Melt butter and let cool slightly.1 cup (or 2 sticks) unsalted butter
In a stand mixer, using the paddle attachment beat eggs & sugar for 5–10 minutes until thick, pale, and fluffy. (This step is key!) 4 extra-large eggs, 2 cups granulated sugar
Sift together cocoa, flour & salt. Gently fold into the egg mixture.¾ cup good quality unsweetened cocoa powder, ½ cup all-purpose flour, Pinch of salt
Slowly mix in the melted butter until just combined.1 cup (or 2 sticks) unsalted butter
Pour into dish. Place the dish in a larger pan and pour hot water halfway up the sides to make a water bath.
Bake 55–60 minutes. The top should look set and crackly, but the inside will be gooey (not fully set like cake).
Let rest 10 minutes, scoop, and serve warm with vanilla ice cream.
Notes
It’s supposed to be pudding-like in the center — that’s the magic!