bomboloni {italian doughnuts}

Name: bomboloni {italian doughnuts}
Prep time: 3 h
Cook time: 10 min
Total time: 3 h 10 min
Cuisine: Italian
Ingredients: 250g (2 cups) bread flour; 250g (2 cups) all-purpose flour; 75g (heaping ⅓ cup) granulated white sugar; 100g (7 tbsp) unsalted butter, at room temperature; 20g fresh cake yeast or 1 package (7g) dry instant yeast; 7g (1½ tsp) salt; 150g (3) whole large eggs; 40g (2) egg yolks; 110g (1/2 cup) lukewarm water; zest of 1 orange; 1 tsp vanilla extract; granulated sugar, for coating