Preparation Steps

• Bloom yeast. Whisk warm milk, the granulated sugar, and yeast in a bowl. Let stand until foamy, 5–10 minutes.
• Beat eggs with vanilla and lemon zest in a large mixing bowl.
• Combine mixtures. Stir the foamy yeast into the egg mixture until smooth.
• Add flour and salt. Mix until a shaggy dough forms.
• Knead and work in butter. Knead 8–10 minutes, gradually adding the softened butter, until silky and elastic.
• Let rise. Place dough in a lightly oiled bowl, cover, and proof until doubled, 60–90 minutes.
• Punch down. Turn onto a floured surface and roll to about 1/2 inch thick.
• Cut rounds with a 2 1/2–3 inch cutter. Set on parchment-lined trays and cover loosely.
• Proof again until puffy and light, about 30–45 minutes.
• Heat oil to 350°F in a deep pot. Keep temperature steady between batches.
• Fry in batches 2–3 minutes per side until deep golden. Drain on a rack or paper towels.
• Coat warm doughnuts in granulated sugar. Cool slightly.
• Fill. Pierce the side, then pipe in pastry cream or jam until just heavy. Dust with powdered sugar if desired.