In a small bowl mix in milk and vinegar and let it stand for 5 to 10 minutes.
In a separate large bowl, mix in all the dry ingredients. To this, add the milk + vinegar mixture, butter and yogurt.
Mix everything till the dough comes together. Let it rest for 40 minutes.
Dust a clean counter/table with flour.
Divide the dough in half and roll the dough to 1/2 inch thickness.
Cut the doughnuts using a 3-3.5 inch cookie cutter/ donut cutter. You can also use two different sized lids for cutting the outer and inner circle of the dough.
Heat oil in a pot up to 185 C. Be very careful when handling hot oil.
Working with 2-3 donuts at a time, cook for 1 minute on each side on medium flame, until they get golden brown.
Carefully remove from the oil after deep frying and place onto a paper towel or kitchen towel (to soak any excess oil). Repeat with remaining donuts.
Keep them on a wire rack to cool to room temperature before adding glaze.
Glaze the donuts with melted white, dark or milk chocolate and add some sprinkles on top.
Dig in!