Sweet Potato Gratin

Ingredients

• 1.5 lbs sweet potatoes (about 2 -3 sweet potatoes, sliced thinly on a mandoline (1/8”))
• 3 Tablespoon butter
• 1/2 cup onion (finely chopped)
• 3 - 4 garlic cloves (finely minced)
• 1 cup heavy whipping cream
• 1 Tablespoon arrowroot starch ((or cornstarch))
• Juice of 1/2 lemon
• 1 cup parmesan cheese (thinly grated)
• Salt and pepper (to taste)
• 1 teaspoon rosemary

Instructions

1. 1

   Preheat the oven to 400 F and grease the sides of a baking dish with butter or olive oil.

2. 2

   Heat butter in a small skillet over medium high heat, add chopped onion, and saute until tender and translucent, about 2-3 minutes. Add minced garlic, and cook for 30 seconds until fragrant. Pour heavy whipping cream and stir. In a small bowl, make a slurry of the warm heavy cream and arrowroot starch. Add back to the skillet and stir well until sauce thickens. Turn off the heat and set aside.

3. 3

   Place sliced sweet potatoes overlapping each other in one layer in the baking dish. Season with salt, pepper, and rosemary. Pour half of the onion mixture, and sprinkle ½ cup of the parmesan cheese on top.

4. 4

   Place another layer of overlapping sweet potato slices on top. Season them with salt, pepper, and rosemary. Pour remaining onion mixture, and sprinkle remaining Parmesan cheese on top.

5. 5

   Bake in a preheated oven for 30 - 40 minutes until the sweet potatoes are tender and cooked through. Let the sweet potato gratin cool for 5 - 10 minutes, and serve warm. The sauce will thicken as it cools.