Caramelized Onion and Blue Cheese Tartine

Instructions

1. Caramelize the onions
   Heat olive oil and butter in a large skillet over medium-low heat. Add the sliced onions and a pinch of salt. Cook, stirring occasionally, for 25-30 minutes until deeply golden and caramelized. Be patient as this process shouldn't be rushed for the best flavor development.
2. Add flavor enhancers
   When onions are golden brown, add the balsamic vinegar, brown sugar, and thyme leaves. Stir to combine and cook for an additional 3-5 minutes until the mixture is sticky and jam-like. Season with salt and pepper to taste.
3. Toast the bread
   While the onions are finishing, toast the sourdough slices until golden brown and crisp on the outside but still slightly soft in the middle. You can use a toaster, grill pan, or broiler for this step.
4. Assemble the tartines
   Spread the caramelized onion mixture generously over each slice of toasted bread. Divide the crumbled blue cheese evenly among the tartines, gently pressing it into the onions.
5. Melt the cheese
   Place the assembled tartines under a preheated broiler for 1-2 minutes, or until the cheese is slightly melted but still maintains some texture. Watch carefully to prevent burning.
6. Finish and serve
   Remove from the broiler and drizzle each tartine with honey. Sprinkle with toasted walnuts and additional fresh thyme leaves. Serve immediately while still warm.