In a large bowl, mix together the flour, salt and baking powder. Cut in the butter until mixture resembles coarse crumbs. Add eggs and milk and stir until dough holds together. Gather dough into a ball, wrap in plastic and chill for at least 2 hours.
Meanwhile, heat olive oil in a large skillet over moderate heat. Add onion and saute until soft, about 10 minutes. Add salt, cayenne pepper and cumin seed and saute another 2 minutes. Add corn, bell pepper, jalapeno chili and chipotle puree and cook for another 5 minutes. Remove from heat and stir in cilantro. Adjust seasoning.
Preheat the oven to 325 degrees F. Remove dough from refrigerator and divide into 4 to 6 pieces. Roll dough to about 9inches in diameter, and 1/4inch thick. Combine egg and water and brush edges of dough with egg wash.
Place about 1/2 cup of filling on one side of each dough circle. Sprinkle filling with 1 tablespoon of grated cheese. Fold dough in half and use a fork to press down on edges and seal shut.
Brush tops of turnovers with egg wash and cut 3 diagonal slits in the top of each turnover.
Place turnovers on a baking sheet lined with parchment paper and bake in preheated oven for about 20 to 25 minutes, or until tops are golden.
To serve, spoon warm Tomato Sauce onto plates, cut warm turnovers in half and place on plates.
Heat 1 tablespoon of the oil in a large skillet over medium high heat. Add whole tomatoes and roast until the skins char and begin to split and peel away. Add garlic cloves and roast until golden, about 2 more minutes. Transfer tomatoes to a blender. Pour vinegar into skillet with garlic and cook for about 2 minutes to reduce vinegar slightly.
Add the garlic and vinegar reduction, to the blender, along with salt and pepper. Process until pureed. Slowly drizzle in remaining 1/2 cup olive oil while pulsing until incorporated.
Return sauce to a small saucepan and keep warm until ready to serve.
Copyright 1996, M.S. Milliken & S. Feniger, all rights reserved