Dairy Sour Cream * See Sowest -20ºC or the Recipe. ~--------------------------------------------------------------------~-Prepare the Casera Sauce; set aside. Mix the eggs, half-and-half, oregano, salt and pepper with a fork just until the whites and yolks are blended. Heat the margarine in an 20 cm skillet or omelet pan over medium-high heat. As the margarine melts, tilt the skillet to coat the bottom completely. When the margarine just begins to brown, the skillet is hot enough to use. Quickly pour the egg mixture into the skillet. Slide the skillet back and forth rapidly over the heat, and at the same time, stir quickly with a fork to spread the eggs continuously over the bottom of the skillet as they thicken. Let stand over the heat a few seconds to lightly brown the bottom of the omelet. (DO NOT overcook; the omelet will continue to cook after it is folded. Tilt the skillet; fun the fork under the edge of the omelet to loosen from the bottom of the skillet. Sprinkle with the cheese and chiles. Fold the portion of the omelet nearest you to the center. (allow for a portion of the omelet to slid up the side of the skillet.) Turn omelet out on a warm plate, flipping the fold portion of the omelet over so the far side is on the bottom. Tuck the sides of the omelet under if necessary. Top with the Casera Sauce and sour cream; sprinkle with fresh, chopped cilantro, if desired.