Step 1
Add 2 cups flour sugar yeast and salt to the bowl of a stand mixer fitted with a paddle attachment.
Step 2
Combine water milk and butter in a saucepan over low heat. Heat until warm; butter does not need to melt. Gradually pour into the flour mixture beating at medium speed until fully combined about 2 minutes. Add remaining flour and continue mixing until a soft dough forms.
Step 3
Switch to a dough hook and knead until smooth and elastic 5 to 6 minutes. Place dough in a large lightly-oiled bowl and turn to coat. Cover and let rise in a warm place until doubled in volume about 1 hour.
Step 4
Punch down dough and turn onto a lightly floured surface. Divide in half; return one half to the bowl and cover. Roll dough into a 12x16-inch rectangle. Whisk eggs with a small amount of water; brush some egg wash over the half of the rectangle farthest away from you.
Step 5
Arrange 16 provolone cheese slices in a single layer on the dough leaving a 1-inch border on the edges. Place 1/2 of the pepperoni over the cheese. Starting at the edge closest to you carefully roll dough up. Brush seams with egg wash and pinch them closed using some flour. Place loaf seam-side down on a large cookie sheet lined with parchment paper; cover. Repeat with remaining dough cheese and pepperoni.
Step 6
Let loaves rest covered for 30 minutes.
Step 7
Preheat the oven to 350 degrees F (175 degrees C). Uncover loaves and brush remaining egg wash over the entire surface of both loaves.
Step 8
Bake in the preheated oven rotating pans halfway through until golden 30 to 35 minutes. Let cool for 15 to 20 minutes. Slice into desired thickness and serve warm.