Unfold 1 pastry crust on floured surface. Roll into 13-inch circle. Cut dough into 16 rounds using a 3-inch pastry cutter, re-rolling scraps as necessary. Repeat with remaining crusts to make 32 circles.
Spoon 1 teaspoon cheese mixture in center of each dough round. Fold round in half, sealing edges with the tines of a fork.
Place empanadas on wax paper-lined baking sheets; freeze, uncovered, for 1 hour or until firm. Place in resealable plastic food storage bags. Freeze up to 2 months, if desired.
To complete recipe, preheat oven to 400 degrees. Place frozen empanadas on ungreased baking sheet. Beat egg and 1 tablespoon water in a small bowl. Brush on empanadas. Sprinkle with chili powder.
Bake 12-17 minutes or until golden brown. Remove from baking sheet to a wire rack to cool ... or better yet, serve them immediately with sour cream and salsa.