1
Pre-heat the oven to 325°F on bake.
2
-
6
tbsp
butter, unsalted (cut into 1tbsp pieces)
-
50
g
chocolate, bittersweet (chopped)
-
⅓
cup
cocoa powder, unsweetened
Melt the butter and chocolate in a cast iron pan over low heat. Mix in the cocoa powder and stir until smooth (2–4min). Set aside to cool slightly.
3
-
100
g
flour, all-purpose
-
2
tsp
baking powder
-
¼
tsp
salt
Whisk the flour, baking powder, and salt together in a bowl and set aside.
4
In a separate bowl, whisk together the sugar and cocoa. Be sure to break up all clumps with your fingers, if necessary.
5
Combine the coffee and water in a large measuring cup.
6
-
⅔
cup
sugar, granulated
-
⅓
cup
milk, whole
-
1
tbsp
vanilla extract
-
1
egg yolk
Whisk the listed ingredients in with the cooled chocolate mixure. Whisk in the flour mixture until just barely combined. Sprinkle the brown sugar mixture over the top. Gently pour the coffee mixture over the whole thing.
7
Transfer the pan to the oven and bake until puffed and starting to pull away from the sides (about 35min), rotating the pan half-way through. Then, transfer the entire pan to a cooling rack for 15min before serving in the pan.