Place pastry sheet on work surface. Cut in
half, forming two 9 1/2x4 3/4-inch rectangles.
Arrange half of prosciutto on 1 rectangle,
leaving 1/2-inch border along 1 side. Sprinkle
prosciutto with half of basil, then top with
half of cheese. Brush plain border with egg
glaze. Starting at long side opposite border,
roll up pastry jelly-roll style, pressing
gently to seal long edges. Wrap in plastic.
Repeat with remaining pastry, prosciutto,
basil, cheese, and egg to form second log.
Refrigerate until firm, at least 3 hours and up
to 2 days.
Position rack in center of oven and preheat to
400°F. Line 2 large baking sheets with
parchment paper. Cut logs crosswise into 1/2-
inch-thick rounds. Arrange rounds on prepared
sheets, spacing 1 inch apart. Bake 1 sheet at a
time until pastries are golden brown, about 16
minutes. Using metal spatula, transfer pastries
to racks and cool slightly. Serve warm.