On lightly floured surface, roll out half of the pastry to 12x10 in rectangle.

Spread with half of the mustard, leaving 1/2 inch border. Sprinkle w. half of the cheese, arrange half of the prosciutto in single layer over cheese. Brush border w. water.

Starting at short end, roll up jelly roll-style just to center of rectangle. Roll up other end to meet in center; turn over. Using serrated knife, trim ends; cut into 1/2 in thick slices.Place on parchment paper-lined baking sheets; press lightly.

Repeat w. remaining ingredients. Cover and refrigerate for 1 hour. (Rollups can be prepared to this point and refrigerated for up to 1 day)

Brush egg over roll-ups.Bake in 400 F oven for 15 to 18 mins or until puffed and lightly golden. Makes about 20 hors d'oeuvres.