Heat the milk over low heat (body temperature). Test with your finger (don't burn!). If the milk is too hot it will “kill” the yeast.
Pour the milk in a measuring jug and add the sugar and yeast.
Place the flour, cacao, salt in a mixing bowl of a food processor with a dough hook.
Add the milk mixture to the flour and mix until it forms a dough. (It should not be smooth.) Add the butter piece by piece and mix until smooth and pulls away from the sides. It should form a ball.
Cover the mixing bowl with cling wrap and leave in a warm place to rise double in size.
Turn the dough onto a clean work surface dusted with flour. Knead a little and divide in two. Roll out one piece, 2 cm thick. Cut with a 4 cm cookie cutter into small round doughnut circles. Dip the cookie cutter into flour to make it easier to cut the dough. Place the doughnuts on a baking sheet and cover slightly with cling wrap. Let it rise 30 minutes till double the size.
Prepare the caramel sauce when the second batch of dough rises.
Heat the oil in a medium casserole. Keep a slotted spoon ready on a plate with kitchen paper towels. Test the heat of the oil by frying a small piece of dough.
Deep fry the doughnuts until golden and cooked. Lift out with a slotted spoon and drain on a kitchen towel.
Pour the warm caramel sauce over the doughnuts.
Whisky Caramel sauce
Heat the cream, butter and vanilla in a small casserole over medium heat. Stir until sugar is dissolved. The sugar must not crystallize.
Increase the heat and allow the mixture to boil until it has a caramel colour. Do not stir again.
The caramel will be translucent and thick, but will change into a darker colour. Do not let it burn. Remove from the heat and add the cream slowly. Stir with a wire whisk until smooth and then add the whisky.
Let the sauce cool in the casserole or pour in a heat resistant bowl. Pour the sauce over the donuts before serving.