1/2 cup chopped herbs, such as parsley, chives and dill
Butter, for greasing baking dish
4 medium sweet potatoes, sliced
1 medium onion, sliced
1/2 cup Parmesan cheese, plus additional for sprinkling
1/2 cup cheddar cheese
Preheat oven to 375°F.
Whisk together cream, eggs, lemon juice, hot sauce, garlic and onion powders, salt, pepper and herbs.
Grease the bottom of a baking dish with butter. Arrange an even layer of sweet potatoes on the bottom of the dish, top with a third of the onions, 1/3 of the parm and 1/3 of the cheddar. Repeat procedure two more times finishing with cheddar cheese.
Pour cream mixture over the top and push potatoes down to allow the cream mixture to be absorbed.
Cover with aluminum foil and bake 45 minutes. Uncover and bake an additional 1 hour and 20 minutes, until cream is absorbed and the top is brown. Let rest for 10 minutes before slicing.