Time: 1 hour, plus at least 4 hours for chilling and 30 minutes for rising
¼ cup lukewarm milk or water
1 teaspoon dry yeast
3 tablespoons sugar
1 whole egg plus 1 egg yolk
3 tablespoons sour cream or vegetable oil
Pinch salt
¼ teaspoon vanilla extract
Freshly grated zest of ½ orange
1 2/3 cups unbleached all-purpose flour, more as needed
½ cup thick raspberry or strawberry jam
Oil for deep-frying
Confectioners' sugar for dusting.
1. Place milk or water in small bowl. Sprinkle yeast and 1 teaspoon sugar over milk. Set aside until frothy, about 10 minutes.
2. In a mixer fitted with paddle attachment, beat remaining sugar with egg and egg yolk. Add sour cream, salt, vanilla extract, orange zest and yeast mixture, and mix well. With mixer running, gradually add flour. Mix until dough is soft, smooth and elastic, adding flour if dough seems very sticky, 3 to 5 minutes. Do not add more than an additional 3 tablespoons flour; dough will be somewhat sticky, but will firm up in refrigerator. Place in an oiled bowl, cover, and refrigerate at least 4 hours or overnight.
3. On a floured surface, roll out dough to ½-inch thickness. Use a biscuit or a cookie cutter to cut out 2-inch rounds, placing them on a parchment-lined baking sheet. Reroll scraps and cut again. Let rise in a warm place 30 minutes.
4. In a heavy pot, heat 3 inches of oil to 365 degrees; when hot enough, a small piece of dough will brown on bottom in 30 seconds. If too hot, doughnuts will brown outside before cooking through. Working in batches, fry doughnuts until golden brown, turning once. Drain on paper towels and dust with sugar while still warm. Let oil come back to 365 degrees between batches.
5. If you have a pastry bag, fit with a small round tip and spoon jam into bag. When doughnuts are cool enough to handle, use tip of bag (or pointed tip of a serrated knife) to make a hole in bottom of doughnut. Squeeze or use a small spoon to nudge ½ teaspoon jam into hole. Repeat with remaining doughnuts and serve immediately. Dust again with powdered sugar.
