This is a basic recipe for what the Dutch call 'Oliebollen'. We make these type of doughnuts for many celebrations throughout the year. This version has added raisins and currants. Sprinkle with icing sugar to serve. They're delicious warm or cold!
Place the raisins and currants in a bowl of warm water and let them soak for at least half an hour. Drain and pat dry with kitchen paper.
Dissolve the yeast in a small amount of lukewarm milk, about 2 or 3 tablespoons. Stir in the flour, salt, remaining milk and one egg; mix with electric beaters until smooth.
Stir the raisins into the batter. Cover the bowl with a clean tea towel and leave to rise in a warm place for about an hour.
Heat oil to 190 degrees C in a deep frying pan. You can test if the oil is hot enough by adding a small piece of bread. If it sizzles and rises to the top, the oil is hot enough to start cooking.
The doughnut batter should be thick and drop easily off a spoon. Use two, lightly greased, tablespoons or an ice cream scoop to spoon the batter into the frying pan. Cook for about 6 minutes, turning half way through, until golden brown.
Let the doughnuts drain on kitchen paper. Sprinkle with icing sugar to serve and eat hot or cold.