Caramelized French Onion Sweet Potatoes

Instructions:

1. Melt 3 tbsp (42g) of butter in a sauté pan over medium-low heat.
2. Add sliced onions and salt. Cook, stirring occasionally, for 40 minutes until the onions are a deep mahogany-brown and smell intensely sweet and nutty.
3. Stir in thyme during the last 2 minutes of caramelizing onions, then remove from heat.
4. Preheat your oven to 375°F (190°C).
5. Toss the sweet potato rounds with melted butter, minced garlic, and black pepper in a large bowl until evenly coated.
6. Arrange the slices in the baking dish, overlapping them slightly in a shingled pattern.
7. In a small bowl, whisk cornstarch into the beef broth until dissolved, then stir in the heavy cream.
8. Pour the cream mixture evenly over the potatoes.
9. Top with the caramelized onions, followed by the shredded Gruyère and Parmesan.
10. Cover with foil and bake for 45 minutes.
11. Remove foil and bake for another 15–20 minutes until the cheese is bubbling and has formed a golden-brown, shattering crust.