3 gruyeere onion sandwiches Recipes

olive oil, onions, sliced thin, chopped fresh rosemary leaves or 1/4 tsp dried, crumbled, white-wine vinegar, rye bread, granny smith apple, sliced gruyere cheese (use a cheese plane if possible)

olive oil, onions, thinly sliced, red wine vinegar, dark brown sugar, caraway seeds, fully cooked smoked sausages (such as white bratwurst or chicken-apple), rye or pumpernickel bread, dijon mustard, gruyere or emmenthal cheese, thinly sliced, butter, room temperature