Prosciuto and Gruyere Pinwheels (Appetizer)

(from Gourmet Magazine, Dec 1996)
¾ cup (3 oz) finely grated Gruyere (cheese)
4 teaspoons chopped fresh sage leaves
1 puff pastry sheet (from one 17 ¼ oz pkg. frozen puff pastry sheets), thawed
1 large egg, beaten lightly
2 oz. thinly sliced prosciuto (ham)
In a bowl, combine Gruyere and sage. On a lightly floured surface, arrange pastry sheet with a short side facing you and cut in half crosswise. Arrange one half of sheet with a long side facing you, and brush edge of far side with some egg. Arrange half of prosciuto evenly on top of pastry, avoiding egg-brushed edge, and top with half of Gruyere mixture. Starting with side nearest you, roll pastry jelly-roll fashion into a log and wrap in wax paper. Make another log in the same manner. Chill pastry logs, seam sides down, until firm, at least 3 hours, and up to 3 days.
Preheat oven to 400F. Lightly grease 2 large baking sheets. Cut logs crosswise into ½-inch thick pinwheels and arrange, cut sides down, 2 inch apart on baking sheets. Bake pinwheels in batches in middle of oven until golden, 14-16 minutes. Transfer pinwheels to a rack and cool slightly. Serve warm. Makes about 40.