# What You’ll Need:
→ Pasta
01 - 12 oz (340 g) rigatoni or penne
→ Onions
02 - 3 large yellow onions, thinly sliced
03 - 2 tbsp unsalted butter
04 - 1 tbsp olive oil
05 - 1/2 tsp salt
06 - 1/4 tsp freshly ground black pepper
07 - 1 tsp sugar
08 - 2 cloves garlic, minced
09 - 1 tsp fresh thyme leaves (or 1/2 tsp dried)
→ Sauce & Assembly
10 - 1/2 cup (120 ml) dry white wine
11 - 2 cups (480 ml) vegetable broth
12 - 2 tsp Worcestershire sauce
13 - 1 tbsp all-purpose flour
14 - 1 cup (240 ml) heavy cream
15 - 1 1/2 cups (150 g) grated Gruyère cheese, divided
16 - 1/2 cup (50 g) grated Parmesan cheese
17 - 1 tbsp chopped fresh parsley (for garnish)
# Step-by-Step Guide:
01 - Preheat oven to 400°F (200°C). Grease a 9x13-inch (23x33 cm) baking dish.
02 - Cook pasta in salted boiling water until just shy of al dente. Drain and set aside.
03 - In a large skillet over medium heat, melt butter and olive oil. Add onions, salt, pepper, and sugar. Cook, stirring often, until onions are deeply golden brown and caramelized, 25–30 minutes.
04 - Add garlic and thyme, and cook for 1 minute until fragrant.
05 - Stir in flour and cook for 1 minute. Pour in white wine, scraping up browned bits. Simmer 2 minutes.
06 - Add vegetable broth and Worcestershire sauce, bring to a simmer, and cook 2–3 minutes more.
07 - Reduce heat to low. Stir in cream and 1 cup (100 g) Gruyère cheese until melted.
08 - Add cooked pasta and Parmesan to the skillet, tossing to combine.
09 - Transfer mixture to the prepared baking dish. Sprinkle remaining Gruyère on top.
10 - Bake 20–25 minutes, until bubbly and golden.
11 - Garnish with parsley before serving.
