2 T bsp instant or bread machine yeast
¼ cup warm water
1 cup warm milk or water
1/3 cup oil or pareve shortening
1/3 cup sugar
½ tsp salt
2 eggs
2 egg yolks
4-5 cups all-purpose flour, as necessary
1½ cups jam or jelly for filling (strawberry or raspberry)
Oil for frying
Granulated superfine sugar

1. In a large mixer bowl, whisk the yeast with the 1/4 cup of water and let stand 2-3 minutes.
2. Add the 1 cup of milk and oil or shortening. Let the mixture cool a bit and then add the sugar, salt, eggs and yolks. Stir well and pour into the yeast mixture.
3. Add the flour and stir on low speed to form a soft dough. Increase the mixer speed to medium and knead for 5-8 minutes, adding a bit of flour as needed to form a firmer dough. When the dough is smooth and elastic, remove the dough hook, spray the dough with nonstick cooking spray and cover the bowl with a large plastic bag. Let the dough rise until almost double in size or do a cold rise overnight in the refrigerator.
4. Punch down the dough and pinch off pieces to form small, golf ball-sized balls. Place them on a cookie sheet or plate, cover and let rest for 15 minutes.
5. In a deep fryer or heavy Dutch oven, heat four inches of oil to 375F. Add the doughnuts a few at a time and fry until the undersides are deep brown. Gently turn over once and finish frying the other side. Lift the doughnuts out using a slotted spoon and drain on paper towels.
6. Slit the doughnuts open two-thirds of the way. Pipe or spoon in a tablespoon or so of jelly and gently reseal the  doughnuts. Sprinkle with granulated sugar, if desired. Serve at once.