Roll butter to a thin layer between 2 baking paper. Keep in freezer.
Combine all the ingredients except the butter and dark chocolate drops in the bowl of a stand mixer with the dough hook attachment.
Mix for 5 minutes on the first speed. Knead for 10 minutes on the second speed.
Add in the cold butter and knead until the dough does not stick to the sides of the bowl.
Add dark chocolate drops and mix until just incorporated.
Cover with plastic film and allow rising for 2 hours at room temperature.
Beat down the dough.
Portion Dough into 60g pieces and roll into balls. Keep in fridge for 30 minutes.
Flatten the dough and cut out donut shape with donut cutter.
Allow to proof at 25°C for 40 minutes, or until dough has doubled in volume.
Deep fry in oil at 170°C until golden brown.