- Make the doughnuts: In a stand mixer with the paddle attachment (or with a hand mixer) combine flour, sugar, salt, yeast, eggs, zest, and water until smooth. Add butter to dough and mix until it is incorporated and no longer visible. Form dough into a ball, cover it, and chill overnight in refrigerator. The next day, cut dough into 50-gram pieces and roll into tight, smooth buns. Place buns on a tray coated with cooking spray, leaving lots of room between them. Let rise until doubled in size, about 1 to 2 hours. In a large pot, heat 2 inches of oil until a deep fry thermometer reads 350 degrees. Fry doughnuts in small batches until golden brown, approximately 2 minutes per side. Once cooled, pipe your favorite jam into the doughnuts using a small, long pastry tip until you feel them puff and swell.
- Make the glaze: Mix sugar, vanilla, and enough water together to achieve a glaze of your preferred consistency.Paint or drizzle on donuts and serve