250 ml (1 cup) grated Emmental cheese (plus extra for garnish)
250 ml (1 cup) grated Havarti cheese (plus extra for garnish)
250 ml (1 cup) grated Mozzarella cheese (plus extra for garnish)
Fresh chives, chopped
Steps
In a skillet over medium-high heat, drizzle olive oil and add the sliced onions. Season generously with salt and cook for 2-3 minutes.
Lower the heat, cover, and cook for 10-15 minutes, stirring occasionally.
Once the onions begin to caramelize, add the balsamic vinegar and oregano. Rub the oregano sprigs between your hands to release the leaves while keeping the stems. Cook for another 5 minutes until the onions are golden and caramelized. Remove from heat and set aside.
Meanwhile, bring a large pot of salted water to a boil. Add the pasta and cook according to package instructions. Drain and set aside.
Preheat the oven to 375°F (190°C).
In a large deep pan or Dutch oven, melt the butter over medium heat. Add the flour and cook for 1 minute while stirring.
Gradually whisk in the milk and bring to a boil. Reduce heat and let it simmer for 1-2 minutes until slightly thickened.
Gradually add the cheeses, stirring constantly, and season with salt and pepper.
Stir in the cooked pasta and half the caramelized onions. Mix well.
Transfer the pasta mixture to an oven-safe dish. Top with the remaining caramelized onions and extra cheese.
Bake for 15-18 minutes, then broil for 2-3 minutes for a golden finish.
