Make the grilled corn salsa:
Soak the corn (with husks) in cold water for 30 minutes. Meanwhile, prepare a medium-high gas or charcoal grill fire.
Wrap each wet corn cob separately in aluminum foil. Space them at least 1 inch apart on the grill and cook, covered, rolling each ear a quarter turn every 8 minutes until the cobs have made a complete rotation, 32 minutes total. Remove the foil, let the ears cool enough to handle, and remove the husks and silk.
Set one ear aside and put the remaining five back on the grill. Cook, turning the cobs once, until they are lightly charred, 2 to 3 minutes. Cool the corn on a rack.
Cut the charred corn from the cobs and put it in a medium bowl. Stir in the lime juice, oil, and chives and season to taste with salt and pepper.
Make the poblano cream sauce:
Char the poblanos on the grill, turning them with tongs as soon as each side becomes fully blackened, 6 to 10 minutes. Put the charred poblanos in a bowl and cover. When cool enough to handle, peel and seed them.
In a heavy-duty 2-quart saucepan, bring the cream to a boil over high heat. Lower the heat to medium and simmer until reduced to 1/2 cup, about 5 minutes.
Heat the oil in a 10-inch skillet over medium heat. Add the onion and garlic and cook, stirring occasionally, until softened but not browned, 3 to 5 minutes. Put the onion mixture, poblanos, and 2 Tbs. water in a blender and puree until smooth. Stir the poblano puree into the reduced cream and season to taste with salt. Keep warm.
Make the empanadas:
Position racks in the top and bottom thirds of the oven and heat the oven to 400°F.
Cut the uncharred corn from the cob. In a medium bowl, stir together the corn, crabmeat, scallion greens, lime juice, 1 tsp. salt, and a few grinds of pepper.
Beat the egg in small bowl with 1 Tbs. of water.
Cut each puff pastry sheet into four 3-1/2-inch squares. Drop 1 rounded Tbs. of the crab mixture in the center of each pastry square. With a pastry brush, brush two adjoining edges of each square with the egg and fold the opposite corner over to form a triangle, sealing all the way around with your thumb. Press a fork down on the sealed edges at regular intervals to form small ridges. Transfer the empanadas to two parchment-lined baking sheets. Bake until golden brown, 15 to 18 minutes, rotating the pans halfway through baking.
Pour 1 Tbs. of the warm poblano cream sauce in a circle around a small plate. Put one empanada in the center of the plate and spoon a little corn salsa to the side. Serve immediately.
Make Ahead Tips
You can assemble and freeze some or all of the empanadas to bake later. Freeze them on a baking sheet and then store in a ziptop bag for up to a month. To bake, heat the oven to 475°F. Put the frozen empanadas on a parchment-lined baking sheet, reduce the oven temperature to 400°F, and bake until golden brown, 20 to 25 minutes.
The corn salsa can be made up to 8 hours ahead and refrigerated, but don't add the chives until just before serving. Serve at room temperature.
The poblano cream sauce can be made up to 4 hours ahead; reheat before serving.
nutrition information (per serving):
Photo: Scott Phillips