Casatiello (Neapolitan Savory Easter Bread)

Make the sponge.

Beat the eggs, sugar and salt together in a large mixing bowl. Add 1 cup of flour and stir until smooth. Cut the sponge into small pieces and add them to the dough mixture. Beat together, then add the remaining flour and mix with your hands to a shaggy mass. Mix in the butter. Sprinkle the dough with the grated cheeses and knead them in with your hands. Continue kneading on a lightly floured surface until the dough is elastic, supple and fairly smooth, 5 to 10 minutes. Place in a lightly oiled bowl, cover with plastic wrap and let the dough rise until almost tripled, about 1-1/2 hours.

Turn dough out on a lightly floured surface and pat and roll into a large rectangle about 3/4-inch thick. Sprinkle half the provolone, half the salami and half the pepper over the surface. Fold into thirds, like a business letter; then roll the dough out again 3/4-inch thick. Sprinkle with the remaining provolone, salami and pepper and fold again into thirds. Gently knead for 2 to 3 minutes to distribute the cheese and salami evenly. Cut the dough in half and knead each half gently into a round ball. Place each ball in a buttered 2-quart charlotte mold or souffle dish. The dough should fill about half the mold. Cover with a towel and let rise to the tops of the molds, about 1-1/2 hours.

Heat oven to 400 degrees (F). Brush the top of each loaf with lightly beaten egg white. Place in the oven and bake for 45 minutes, until the tops are very brown and shiny. Remove from the molds and cool on racks.