01 -
Preheat your oven to 375°F (190°C). In a greased baking dish, layer half of the sweet potato slices at the bottom.
02 -
Spread the chopped spinach evenly over the sweet potatoes. Sprinkle half of the grated Gruyere cheese over the spinach.
03 -
In a bowl, whisk together the heavy cream, milk, garlic powder, salt, and pepper. Pour half of this mixture over the layered vegetables.
04 -
Repeat the layers with the remaining sweet potatoes, spinach, and Gruyere cheese. Pour the remaining cream mixture on top.
05 -
In a small bowl, combine breadcrumbs with olive oil, mixing until well coated. Sprinkle the breadcrumb mixture evenly over the top of the gratin.
06 -
Cover the baking dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 15-20 minutes, or until the top is golden brown and the sweet potatoes are tender.
07 -
Remove from the oven and let it cool for a few minutes. Garnish with fresh thyme leaves before serving.