Cheddar and Prosciutto Biscuits with Rosemary I

Name: Cheddar and Prosciutto Biscuits with Rosemary I
Ingredients: 4 cups unbleached all-purpose flour; 2 cups white whole wheat flour (milled from white wheat grains); 1/4 cup minced fresh rosemary; 2 tablespoons baking powder; 2 teaspoons coarse salt; 1 teaspoon cracked black pepper; 1 1/2 cups (3 sticks) cold butter, cut into 1/4-inch pieces; 2 cups shredded sharp cheddar cheese (8 ounces); 3 ounces prosciutto, finely chopped (3/4 cup); 2 1/4 cups cold buttermilk, plus more for brushing