1Generously grease 15x10x1-inch pan with shortening or cooking spray. In medium bowl, beat flour, milk, sugar, vanilla, salt and eggs with wire whisk until smooth.
2Arrange bread slices to fit in single layer in pan. Pour egg mixture over bread slices; turn to coat both sides. Cover and refrigerate at least 8 hours but no longer than 24 hours.
3Heat oven to 450°F. Uncover; bake 10 to 13 minutes or until golden brown.
4Meanwhile, in 2-quart saucepan, heat strawberries, rhubarb and water to boiling. Boil 5 minutes, stirring occasionally; remove from heat. Stir in gelatin until dissolved. Boil 2 minutes longer, stirring constantly. Serve warm sauce with French toast.