Baked Crab And Corn Empanadas With Roasted Poblano Sauce

In a large bowl, combine the crab meat, scallions, corn, and lime juice. Season with salt and pepper.
Cut each sheet of pastry into 4 squares. Place one rounded tablespoon of the crab and corn mixture into the center of each square. Brush the edges of the pastry with the egg, then fold it over to form a triangle with the filling inside. Use the tines of a fork to seal the pastry by crimping the edges together. Brush the top of the pastry with the remaining egg.
Arrange on a parchment-lined baking sheet and bake at 400 degrees for 20 minutes, or until golden brown.
While the empanadas are baking, light a grill or broiler to high. Place the chiles on the grill/under the broiler and cook for several minutes until the skins turn black and begin to blister. Remove and allow to cool. Remove the papery leaves from the tomatillos and add those. Cook 1-2 minutes or until they just begin to soften. Remove and let cool.
Remove the stem and seed core from the peppers. Use a knife to scrape away the outermost layer of skin (it will be very thin and film-like and should peel off fairly easily). Chop.
Use a blender or food processor to puree the tomatillos. Add the tomatillo puree, chopped chiles, broth, onion, garlic, oregano, salt, and pepper to a saucepan and bring to a boil. Reduce heat and let simmer for 10 minutes. Whisk in the cornstarch and let simmer another 10 minutes, or until the sauce is thickened.
Serve the empanadas in a pool of sauce.