- 2 packages active dry yeast
- ½ cup warm milk (110 to 115°F)
- 4 large eggs
- ¼ cup fruity olive oil
- ¼ cup (½ stick) unsalted butter, melted and cooled
- 3½ to 4 cups unbleached all-purpose flour
- ½ teaspoon salt
- 1 teaspoon freshly ground black pepper
- 1 cup freshly grated Pecorino Romano cheese
- ½ cup shredded Swiss or Fontina cheese
- 4 ounces thinly sliced prosciutto, cut into thin shreds
- Stir the yeast into the milk in a large mixing bowl and let stand until dissolved, 5 to 10 minutes. Beat in the eggs, olive oil, and butter until well blended. Combine 3½ cups flour with the salt and pepper, add it to the yeast mixture, and stir to form a dough. Work in the cheeses and the prosciutto.
- Transfer the dough to a floured work surface and knead, adding more flour if the dough is too sticky, until smooth and satiny, 7 to 10 minutes. Shape the dough into 1 round and bulbous loaf. Place on a baking sheet lined with parchment paper. Cover with a clean kitchen towel and let rise in a warm, draft-free place until doubled in bulk, 1½ to 2 hours.
- Preheat the oven to 400° F.
- Bake the bread until the loaf sounds hollow when tapped on the bottom, 30 to 40 minutes. Let cool on a wire rack.