
Ingredients
1T Olive oil
1T Unsalted butter
2C Red onion, halved and thinly sliced
2t Brown sugar (either light or dark)
Salt to taste
1T Balsamic vinegar
Freshly ground black pepper to taste
4ea 1/2″ slices of rye bread
2T Softened butter
1/4C Grated Emmenthaler or other Swiss cheese
Process
Heat the olive oil and 1T butter in a large skillet over medium-high heat
Add the onions and sauté for 5 minutes
Add the brown sugar and salt
Lower the temperature to medium-low and cook another 10 minutes, stirring occasionally
Add the vinegar, and scrape any stuck onion bits from the bottom of the pan
Simmer for 1-2 minutes, until the onion mixture thickens
Season to taste with freshly ground black pepper
Cool to lukewarm, or store in an airtight container in the refrigerator until needed for up to 5 days
You should have just shy of 1/2C of cooked onions
Assemble the sandwiches
Generously butter one side of each slice of bread
Arrange one slice butter side down on a plate
Spread the top side thickly with onion jam (about 2T)
Sprinkle with 1/2 of the grated cheese
Arrange a second slice of bread butter side up on top of the cheese
Repeat with the second sandwich
Heat a heavy 12 inch skillet over medium-low heat
Arrange the sandwiches in the pan and cook until crisp and deep golden brown (about 5 minutes each side)
If you are making a large batch you can keep the finished sandwiches in a 200F oven
When ready to eat, slice the sandwiches in half