A luxurious sweet potato casserole recipe rich with cream, butter, cheese, herbs, and garlic.
Preheat the oven to 400 degrees F. Pull the leaves off the thyme stems. Discard the stems and roughly chop the leaves.
Place the cream and cornstarch in a small bowl or pot. Whisk well. Add the butter, garlic, thyme, 1 1/4 teaspoon salt, and 1/2 teaspoon pepper. Heat over the stovetop, or in the microwave, just until the butter melts. Then turn off the heat and whisk again.
Peel and slice each sweet potato one by one. Slice the potatoes into very thin rounds, 1/8-inch thick. Arrange each potato in a 9x13-inch baking dish, fanning it out in a pretty pattern.
Before peeling and slicing the next sweet potato, pour a little of the cream mixture over the potato slices in the pan, so it does not brown while you work on the other potatoes.
Repeat until all the sweet potatoes are sliced and arranged prettily in the baking dish. Then pour the remaining cream mixture over the top.
Bake for 30 minutes. Sprinkle Parmesan cheese over the sweet potatoes. Then bake another 10 minutes until the cheese is golden. Serve warm.