Whirl flour, sugar, salt in processor until mixed. Add butter; pulse until texture of coarse meal. Add water, tablespoon at a time, and pulse until dough begins to come together. Place on plastic wrap; shape into rectangle; wrap; chill 30 minutes.
Beat softened cream cheese, sugar, cinnamon, yolk in bowl.
Heat oven to 400°F.
Cut dough into 6 equal pieces. On floured surface, roll each piece into 4-1/2- to 5-inch circle. Transfer to 2 large baking sheets.
Spread scant tablespoon cream cheese mixture in 2-inch circle in center of each dough circle. Sprinkle each with 1 teaspoon nuts. Top with generous 1/3 cup grapes. Fold pastry up over edges.
Bake in 400°F oven 12 to 15 minutes, until browned, center bubbly. Cool 10 minutes. Dust with sugar.