Peel the potatoes and slice them into thin round slices.
Grease a 6-quart slow cooker.
In a medium bowl, add the cream of mushroom and the heavy cream. Add the dried thyme and parsley and whisk well to combine ingredients.
Add a layer of sliced potatoes to the bottom of the crockpot, in an overlapping pattern. Season the potatoes with salt and pepper, to taste.
Add about 1/3 of the mushroom soup-heavy cream mixture over the potatoes and then sprinkle with cheddar cheese.
Repeat with remaining potato slices, cream mixture, and shredded cheddar cheese in that sequence, ending on top with a layer of potatoes. Leave about a quarter cup of shredded cheese to garnish the top at the end of the cooking time. In total there will be 4 layers of potato, 3 layers of mushroom soup-heavy cream mixture, and 3 layers of shredded cheese.
Cover the crock pot and cook on high heat for 4 hours. Sprinkle the top with the reserved cheese. Cover for about 5 minutes, till the cheese is melted.
Garnish with chopped fresh parsley and serve immediately.