Karen'S Crispy Onion Rings
["3 large onions, cut in 1/2-inch rounds", "1 c. flour", "1/2 c. cornstarch (for crispness)", "1 tsp. soda", "1/2 tsp. salt", "1 1/2 c. water", "vegetable oil for frying"]
["Separate onions into rings.", "Soak in ice water for about 2 hours.", "Combine dry ingredients in large bowl.", "Whisk in water all at once until batter is smooth.", "Refrigerate 1 to 2 hours before using."]
["onions", "flour", "cornstarch", "soda", "salt", "water", "vegetable oil"]