Melt 1 tablespoon butter in skillet. Add onions and cook 3 minutes. Stir in crab and green chiles. In another pan melt remaining butter. Add flour. Stir in milk all at once. Add cilantro, salt and pepper. Cook over medium high heat until mixture thickens and bubbles. Stir in sour cream and 1/2 cup Jack cheese until melted. Remove from heat. Stir remain- ing 1 cup cheese and cheese sauce mixture into crab mixture. Spoon 2 tablespoons cheese sauce into bottom of 12 x 7-inch or 13 x 9-inch baking dish. Fill flour tortillas with crab filling. Place filled tortillas seam side down in baking dish. Pour remaining cheese sauce over tortillas. Sprinkle remaining 1 cup cheese over all. Bake at 350 degrees about 30 minutes or until hot and bubbly. Serve at once garnished with avocado and olives if desired. Makes 4 servings. Posted to recipelu-digest by "Diane Geary" on Feb 22, 1998