1. In a medium mixing bowl combine egg, 1/4 cup of the yogurt, the mayonnaise or salad dressing, parsley, Worcestershire sauce, mustard, paprika, and pepper. Stir in crabmeat and crushed crackers.
2. Shape crab mixture into five 3-inch patties.
3. Spray a shallow baking pan with nonstick spray coating. Arrange patties in pan. Broil 4 to 6 inches from the heat for 10 to 15 minutes or until lightly browned. Do not turn patties during broiling.
4. Serve crab cakes on tomato slices with remaining yogurt. Garnish with lemon wedges, if desired. Makes 5 main-dish servings.
Make-Ahead Tip: Prepare crab patties; cover and chill up to 8 hours. Broil as above.