Preheat oven to 400F.

In a baking pan roast onions in oven for 30 minutes and cool.Peel onions and chop coarse.

In a heavy 10"skillet cook onions and garlic in oil over moderate heat,stirring, until garlic is softened, about 2 minutes, and remove skillet from heat.Add cheese and salt &pepper to taste, stirring until cheese is melted.Cool filling.

Sprinkle cornmeal over a baking sheet. On a lightly floured surface roll out puff pastry1/8"thick .With a 3" round cutter, cut 16 rounds. Put a scant tbsp. of filling in centre of each round.Brush edge of round with egg wash and fold round in half, pressing edges together firmly. Crimp edges with tines of a fork to seal and prick top of each empanada several times with a fork(for steam vents). Transfer empanadas to prepared baking sheet.

Bake empanadas in upper third of oven until puffed and golden brown, about 15 to 20 minutes.Makes 16 empanadas to serve 8.