# List of Ingredients:
→ Pasta
01 - 12 oz ditalini pasta
→ Onions
02 - 4 large yellow onions, thinly sliced
03 - 2 tbsp unsalted butter
04 - 1 tbsp olive oil
05 - 1 tsp sugar
06 - 1/2 tsp salt
→ Sauce
07 - 2 cloves garlic, minced
08 - 1 tbsp all-purpose flour
09 - 1 cup vegetable broth
10 - 1/2 cup heavy cream
11 - 1 tsp fresh thyme leaves or 1/2 tsp dried thyme
12 - 1 tsp Dijon mustard
13 - Freshly ground black pepper, to taste
→ Cheese Topping
14 - 1 cup Gruyère cheese, grated
15 - 1/3 cup Parmesan cheese, grated
16 - Chopped chives or parsley for garnish (optional)
# Step-by-Step Directions:
01 - Boil ditalini pasta in a large pot of salted water until al dente. Reserve 1/2 cup pasta water, drain pasta, and set aside.
02 - Heat butter and olive oil in a large skillet over medium heat. Add sliced onions, sugar, and salt. Cook, stirring frequently, until onions are deeply caramelized and golden brown, about 25 to 30 minutes. Adjust heat to prevent burning.
03 - Incorporate minced garlic into the caramelized onions and sauté for 1 minute until fragrant.
04 - Sprinkle flour over onions, stir well, and cook for 2 minutes to remove raw flour taste.
05 - Pour in vegetable broth, scraping the pan to lift browned bits. Simmer for 2 to 3 minutes until sauce thickens slightly.
06 - Stir in heavy cream, thyme, Dijon mustard, and black pepper. Simmer gently for 3 to 4 minutes until sauce is creamy.
07 - Add cooked pasta and reserved pasta water as needed to achieve desired saucy consistency. Stir gently.
08 - Remove from heat. Fold in half of the Gruyère and all Parmesan until melted and creamy. Adjust seasoning to taste.
09 - Serve immediately, topped with remaining Gruyère cheese and chopped fresh herbs if desired.
