1 large onion, thinly sliced 8 oz white mushrooms, diced 2 tablespoons olive oil 8 slices caraway seeded rye bread 8 deli slices havarti or gouda cheese 2-4 tablespoons butter
- Heat a large skillet over a medium-high flame. Add olive oil and heat.
- Add onions and cook, stirring often, until translucent.
- Add mushrooms and continue sauteing until onions have caramelized and mushrooms have cooked through. Transfer to a plate to cool slightly.
- To assemble sandwiches, layer the mushroom mixture with the cheese between two slices of bread.
- Return skillet to stove over a medium flame and melt 1 tablespoon of butter.
- Place 2 sandwiches in the pan and fry a few minutes on each side, until the bread browns and cheese has melted. Add butter to pan in between sandwiches as needed. Serve hot.