Preheat oven to 350º and cover a baking sheet with parchment paper.

Whisk together flour, baking powder, salt, 3 oz. parmesan, and 1 T. ground pepper.

Cut in cold butter and blend with your fingertips until the mixture is coarse.

Stir in milk and 3 eggs just until dough comes together. It will be very sticky

Divide dough into quarters. Dust your hands with flour and form each quarter into a separate foot-long loaf on the baking sheet.

Whisk remaining egg and brush loaves evenly. Sprinkle remaining parmesan and pepper on top.

Bake at 350º for 30 minutes until golden brown. Remove biscotti, reduce oven to 300°, and let biscotti cool for 10 minutes.

Use a serrated knife to cut loaves diagonally into half-inch slices. Return slices to the baking sheet cut side up.

Continue baking at 300º for 20 minutes on each side. Cool completely on racks before storing.