PREHEAT oven to 400°F. Beat egg and water until blended; set aside. Roll pastry block on lightly floured surface into 14x10-inch rectangle; cut in half lengthwise. Brush both pastry halves lightly with some of the egg mixture.

SPRINKLE 3 Tbsp. of the cheese and the pepper evenly over one of the pastry pieces; cover with ham slices. Place remaining pastry piece, egg-side down, over ham. Roll gently with rolling pin to seal. Brush with additional egg mixture.

ROLL up tightly to form a 14-inch log, starting at one of the long sides. Cut log crosswise into 24 slices. Place, cut-sides down, on parchment-covered baking sheet. Brush with remaining egg mixture; sprinkle with remaining 1 Tbsp. cheese.

BAKE 12 to 14 min. or until golden brown. Serve warm or at room temperature.