First, preheat a large heavy-bottomed pan (such as cast iron) to medium-low heat. Make sure that it's thoroughly preheated - this will take at least 5-10 minutes for a cast iron.
While the pan is preheating, butter one side of each of the sourdough slices. Then, flip over one piece and spread on the caramelized onion jam.
1 tbsp salted butter, 1-2 tbsp caramelized onion jam, 2 slices of sourdough bread
Once the pan is hot, add the sourdough to the pan with the buttered sides down. Allow it to warm up and toast for about 2 minutes.
2.5 slices of bacon, 7-8 thin slices of honeycrisp apple, ⅔ cup shredded sharp cheddar cheese
Then, on the side without the jam, layer on half of the shredded cheddar, followed by the apple slices, bacon strips, and remaining cheddar.
Place the slice of bread with the jam on top. Let it cook for about 3-4 minutes, pressing down on it occasionally with your spatula. Then, carefully flip the sandwich and continue cooking for 3-4 minutes or until golden and cheese is melted.
Optionally, top with a drizzle of hot honey and a few fresh thyme leaves. Enjoy!
hot honey, fresh thyme leaves