• The night before frying the donuts, stir together the 110g whole milk and 1 tbsp. coffee grounds for the mocha custard and let it steep in the fridge overnight.

Chocolate Brioche Donuts

• Add the cocoa powder to the bottom of the bowl of a stand mixer. In a microwave safe measuring cup, heat the milk to 100°F / 38°C. Pour about ½ of the warm milk over the cocoa powder, mixing until no clumps remain. To the rest of the milk, whisk in the yeast and sugar. Set aside until the yeast mixture begins to foam (~5 minutes)
• Add the flour, salt, egg, butter, and yeast mixture to the cocoa powder mixture.
• Knead the dough on low speed for 1 minute to allow the ingredients to come together. Increase the speed to medium-high and knead for an additional 10-20 minutes, or until the dough cleans the sides and bottom of the bowl, and passes the windowpane test.*
• Once the dough is done kneading, butter the inside of the bowl, form the dough into a ball and place it back in the bowl. Then cover the mixing bowl with plastic wrap. At this point, you could set the dough in the fridge to rise overnight, or continue with completing the recipe in one day. If doing in one day, set the dough in a warm area and wait for it to double in size (~1 hour.)
• While waiting for the dough to rise, make the mocha custard.

Mocha Custard

• Add the egg yolk, sugar, corn starch, and salt to a small mixing bowl. Whisk the mixture until combined.
• Pour the steeped coffee ground milk mixture over a fine mesh sieve into a medium sized saucepan to remove the grounds, then heat the milk to a simmer.
• Once the milk is simmering, slowly whisk a little bit of milk at a time into the egg yolk mixture. Be sure to whisk constantly to avoid curdling the eggs.
• Once the two mixtures are combined, pour the mixture back into the saucepan. Set the mixture over medium heat and constantly whisk until it thickens.
• Once it's thickened, pass the custard through a fine mesh sieve into a small mixing bowl. Then, whisk in the butter and chopped chocolate until they melt and the mixture is completely smooth.
• Press plastic wrap directly onto the surface of the custard, and leave it in the fridge until you’re ready to assemble the donuts.

Assembling the Donuts

• Cut out 6 parchment squares that are ~4" each and place them on to a lined baking tray.
• Once the donut dough has doubled in size, punch it down to remove excess air and transfer it to a clean, lightly floured surface.
• Divide the dough into 6 equally sized pieces (~64g each) and roll each tightly into a ball.
• Transfer the donuts to their own parchment square, then gently press down on them to flatten them a little bit. Cover them loosely with a towel and allow them to rise in a warm environment for ~30 minutes, or until they have slightly puffed up.
• Make the coffee sugar by stirring together the sugar and coffee grounds in a shallow bowl.
• Once the donuts have puffed up, fill a large saucepan with at least 2” of vegetable or any neutral oil. Heat the oil to 365°F / 185°C.
• Carefully place the donuts into the hot oil (3-4 at a time, depending on what your pan can comfortably fit). Fry the donuts on each side for 3 minutes. You can also check that they are done by making sure the internal temperature is at least 180°F / 82°C.
• Remove the donuts from the oil and immediately toss them in the coffee sugar.
• Once the donuts are done, finish making the mocha custard. Use a hand mixer or stand mixer to beat the custard for one minute. Then, while still mixing, slowly pour the heavy whipping cream into the custard.
• Once all the heavy cream has been added, continue to beat the mixture for 1-2 minutes, or until it is light and fluffy.
• Transfer the mocha custard to a piping bag fitted with a round tip. Use a sharp knife to poke a hole into the top of each donut, then fill each donut generously with the mocha custard. Serve and enjoy!