Simple, light, and surprisingly good, this is often referred to as James Beard’s favorite sandwich.
Makes 2

1/2 white onion, sliced thin (keep rings together)
4 slices soft bread, crusts removed
Mayonnaise
Salt
Minced fresh parsley or other herbs

Spread 2 slices of bread lightly with mayo and top with 1-2 onion slices (with all rings intact); salt well. Top with remaining bread slices. Spread mayo on edges of sandwiches and dip in fresh herbs to coat.

For elegant appetizers, use a cookie cutter to cut small rounds of bread and continue as directed.