Fluffy Italian doughnuts oozing with warm custard cream are pure morning bliss. These beloved mediterranean pastries are a family breakfast favorite.
Warm the milk until just lukewarm and dissolve the active dry yeast with 1 tablespoon of sugar. Let sit for 10 minutes until frothy.
In a large bowl, combine flour, remaining sugar, salt, lemon zest, and eggs. Add the proofed yeast mixture and mix until a shaggy dough forms.
Knead in the softened butter in increments on a lightly floured surface for 8–10 minutes until smooth and elastic. Let rise, covered, in a warm spot until doubled, about 2 hours.
Punch down the dough and roll out to 3/4 inch thickness. Cut rounds with a 3 inch cutter, place on parchment, cover, and proof for 30–45 minutes until puffy.
Heat canola oil to 340°F (medium heat, use thermometer) in a deep pot. Fry 2–3 doughnuts at a time, turning once, until golden—about 2 minutes per side. Drain on paper towels and cool slightly.
Once cool, fill a piping bag with vanilla pastry cream, poke a hole in each bomboloni and fill generously. Dust with sugar and serve while fresh.