Preheat oven to 400 degrees. In a large bowl combine the heavy cream and milk. Peal potatoes and slice into very thin slices. I use a mandolin because it is much faster and potatoes are the same thickness. As you slice them immediately place them in the bowl with the heavy cream and milk mixture.
After potatoes are sliced, add gruyere and parmigiano cheese to the bowl, along with garlic, leaves from thyme, and Everglades All Purpose Seasoning.
Pour potatoes mixture in 8x11 baking sheet cover tightly with aluminum foil. Make sure to put a baking pan on sheet pan so incase liquid overspills. Cook for one hour while potatoes are covered. Uncover and cook for additional 30 minutes. Let sit for 5 minutes before serving.