For Beer Batter: Combine cornstarch, flour and seasonings. Add beer; mix well. For Seasoned Flour: Combine ingredients and mix well. Cut about 3/4-inch off top of onions and peel. Cut into 12 to 16 vertical wedges, but do not cut through bottom (root end) of the onions. Remove about 1-inch of "petals" from center of onion. Soak cut onions in ice water 10 to 15 minutes. If onion petals do not separate and "bloom," cut petals slightly deeper. Dip cut onion in seasoned flour mixture and remove excess by shaking; dip into batter and remove excess by gently shaking. Separate "petals" to coat thoroughly with beer batter. Gently place onion in fryer basket and deep-fat fry at 375 degrees for 1 to 1-1/2 minutes. Turn over and fry an additional 1 to 1-1/2 minutes longer until golden brown. Repeat with remaining onions. Drain on paper towels. Place onion upright in shallow bowl and serve with Creamy Chili Sauce, if desired. Makes 6 blooms.
Creamy Chili Sauce: combine 1 pint mayonnaise, 1 pint dairy sour cream, 1/2 cup chili sauce, and 1/2 tsp. cayenne pepper. Spoon chili sauce into small cups. Place one cup in center of each bloom and serve. Makes 1 quart.