1 small onion, thinly sliced and separated into rings
1.In bowl, combine SPAM® Classic, 1/2 cup cheese, the celery, bell pepper, mayonnaise and thyme; mix well.
2.Spread one side of each slice bread with butter. Spread 1/2 cup SPAM® mixture on unbuttered side of 6 slices bread. Top each with tomato, onion and about 1 tablespoon remaining cheese. Cover with remaining slices bread, butter-side-up.
3.In skillet or griddle, grill sandwiches over medium heat until cheese is melted and both sides are golden brown.