# Ingredient List:
→ Vegetables
01 - 2 large sweet potatoes, peeled and thinly sliced
02 - 7 ounces fresh spinach, washed and roughly chopped
03 - 1 medium onion, finely chopped
04 - 2 garlic cloves, minced
→ Dairy & Eggs
05 - 7 fluid ounces heavy cream
06 - 3.4 fluid ounces whole milk
07 - 4.2 ounces grated Gruyère or Cheddar cheese
08 - 1 ounce grated Parmesan cheese
09 - 2 tablespoons unsalted butter
10 - 2 large eggs
→ Herbs & Seasonings
11 - 1/2 teaspoon ground nutmeg
12 - 1/2 teaspoon dried thyme
13 - Salt and freshly ground black pepper, to taste
→ Topping
14 - 1 ounce breadcrumbs, gluten-free optional
15 - 1 tablespoon olive oil
# Step-by-Step Instructions:
01 - Preheat the oven to 375°F. Grease a medium baking dish with butter or olive oil.
02 - Melt butter in a large skillet over medium heat. Cook onion until softened, about 4 minutes, then add garlic and cook another minute.
03 - Add the spinach to the skillet and cook until wilted, stirring constantly. Season with salt, pepper, and nutmeg. Remove from heat and set aside.
04 - Whisk together the heavy cream, whole milk, eggs, dried thyme, and half the grated Gruyère cheese. Season with salt and pepper.
05 - Arrange half of the sweet potato slices in the baking dish. Spread the spinach mixture evenly over the potatoes, then layer the remaining sweet potatoes on top.
06 - Pour the cream and cheese mixture evenly over the layered vegetables.
07 - Sprinkle the remaining Gruyère and all the Parmesan cheese evenly over the top. Toss breadcrumbs with olive oil and sprinkle over the gratin.
08 - Cover the dish loosely with aluminum foil and bake for 30 minutes.
09 - Remove the foil and bake an additional 15 minutes until the top is golden and sweet potatoes are tender.
10 - Let the dish rest for 10 minutes before serving to allow flavors to meld and texture to set.
