A lemon donut recipe that will be a hit.
Stir together yeast and warm water in a small bowl until yeast is dissolved. Let stand until foamy, about 5 minutes. (If yeast doesn’t foam, discard and start over with new yeast.)
Mix together flour, milk, butter, yolks, sugar, salt, cinnamon, and yeast mixture in mixer at low speed until a soft dough forms. Increase speed to medium-high and beat 3 minutes more.
Scrape dough into a ball in the center of the bowl, then sprinkle lightly with flour to keep a crust from forming. Cover bowl with a clean kitchen towel and let dough rise in a draft-free place at warm room temperature until doubled in bulk, 1 1/2 to 2 hours.
Turn dough out onto a lightly floured surface and roll out with a lightly floured rolling pin to 1/2 inch thick. Cut out as many rounds as possible with a small round cookie cutter
Make them about 2 inches in diameter.
Transfer doughnuts to a lightly floured large baking sheet. Cover doughnuts with a clean kitchen towel and let rise in a draft-free place at warm room temperature until slightly puffed, about 30 minutes Do not re-roll scraps. If you don't want to waste them, just cook them as odd shaped pieces and coat with powdered sugar.
6Heat 2 1/2 inches oil in a deep 4-quart heavy pot until it registers 350°F on thermometer.
Fry doughnuts, 3-4 at a time, turning occasionally with a wire or mesh skimmer or a slotted spoon, until puffed and golden brown, about 1-2 minutes per batch. Transfer to paper towels to drain. (Return oil to 350°F between batches.) Let cool.
Once the doughnuts are completely cool, fill them with the lemon curd.
Poke a hole on each end of the donut and use a piping tool to fill.When the doughnuts are filled, roll them liberally in powdered sugar, put a dollop of lemon curd on top of each donut.
For the Lemon Curd
Place the zest, juice, sugar, salt, and eggs in a metal bowl. Whisk away.
Add in the butter, clamp on an instant-read thermometer, and set the bowl over a tiny pot of simmering water. You must whisk the full time to prevent the egg from cooking up the edge of the bowl.
Keep cooking and stirring until it’s thick, and the thermometer reads 160°F, 5-10 minutes. Place a fine-mesh sieve over another metal bowl and press the curd through it with a rubber spatula. Cover the surface of the curd with plastic wrap, cool completely, and refrigerate until ready to use.