Preheat oven to 350°. In large bowl, combine all ingredients except bread. In shallow 1-1/2-quart casserole, spoon spinach mixture. Bake 20 minutes or until golden.
Meanwhile, cut bread slices into ''tombstone'' shapes. Arrange in single layer on cookie sheet. Bake 12 minutes or until crisp. Cool completely on wire rack. Decorate, if desired, with additional tinted Mayonnaise*.
To serve, arrange a few ''tombstones'' in cooked dip and serve with remaining ''tombstones'' and your favorite dippers.