Scalloped Sweet Potatoes

These would have been perfect had I used all the exact ingredients, prepped the potatoes as instructed, and cooked the full time. Do as I say, not as I do, and follow the recipe from RealSimple!

Ingredients:
2 medium sweet potatoes (1 pound), peeled
2 medium russet potatoes (1 pound), peeled
2 cloves garlic, crushed
2 tsp. fresh thyme leaves
Salt and Pepper
2 1/2 c. heavy cream
Butter (for the foil)

Directions:

Heat oven to 400 degrees. In a food processor fitted with the thinnest (2 mm) slicing disk, slice the potatoes. In a shallow 1 1/2-quart baking dish, toss the potatoes, garlic, thyme, 3/4 tsp salt, and 1/4 tsp pepper. Add the cream and press gently to submerge the potatoes.
Cover the dish with buttered foil, place on a rimmed baking sheet, and bake for 20 minutes. Remove the foil and bake until the potatoes are tender and the top is golden brown, 25 to 30 minutes.