1THAW pastry sheet at room temperature 40 min or till easy to handle. Heat oven to 400. Lightly grease 2 baking sheets or line with parchment paper.
2Stir egg and water in small bowl. Stir Muenster cheese, Parmesan cheese, onion and garlic powder in medium bowl.
3UNFOLD pastry sheet on lightly floured surface. Brush with egg misture. Top with chesse mixture and spinach. Starting at short side closest to you, roll up like a jelly roll. Cut into 20 (1/2") slices. Place cut side down on baking sheet. Brush with egg mixture.
BAKE 15 mins. or till golden brown Serve worm or at room temperture.