1/2 pound (2 sticks) unsalted butter, plus extra for buttering the dish
4 extra-large eggs, at room temperature
2 cups sugar
3/4 cup good cocoa powder
1/2 cup all-purpose flour
Seeds scraped from 1 vanilla bean (I just added a teaspoon of vanilla)
1 tablespoon framboise liqueur, optional (I omitted)
Vanilla ice cream, for serving
Preheat the oven to 325 degrees F. Lightly butter a 2-quart (9 by 12 by 2-inch) oval baking dish. Melt the 1/2 pound of butter and set aside to cool.
In the bowl of an electric mixer fitted with the paddle attachment, beat the eggs and sugar on medium-high speed for 5 to 10 minutes, until very thick and light yellow. Meanwhile, sift the cocoa powder and flour together and set aside.
When the egg and sugar mixture is ready, reduce the speed to low and add the vanilla seeds, framboise, if using, and the cocoa powder and flour mixture. Mix only until combined. With mixer still on low, slowly pour in the cooled butter and mix again just until combined.
Pour the brownie mixture into the prepared dish and place it in a larger baking pan. Add enough of the hottest tap water to the pan to come halfway up the side of the dish and bake for exactly 1 hour. A cake tester inserted 2 inches from the side will come out 3/4 clean. The center will appear very under-baked; this dessert is between a brownie and a pudding.
Allow to cool (but not too long, who doesn't love warm brownies with cold ice cream melting over top) and serve with vanilla ice cream.