1. Preheat the oven to 375 degrees F. Bring the potatoes to a boil in a large pot of cold water. Salt the water and cook until the potatoes are tender, about 20 to 30 minutes.2. Drain the potatoes, return the potatoes to the pot and mash over low heat, adding 6 tablespoons butter, 3 cups cheddar cheese, yogurt, cream, thyme, garlic powder, onion powder, paprika, and cayenne. Season to taste with salt and pepper. Spoon the potato mixture into a 9x13 inch baking dish. Top with the the remaining 1/2 cup to 1 cup cheddar cheese.3. In a medium bowl, mix together the cracker crumbs, garlic, Worcestershire sauce, and 4 tablespoons butter. Sprinkle the crackers evenly over the potatoes.4. Cover the dish with foil. Transfer to the oven and bake for 30-35 minutes, remove the foil and continue baking another 15 minutes, until the crackers are golden. Serve warm topped with fresh thyme and flaky sea salt.
1. Combine the potatoes and 1 1/2 cups water. Cover and cook on high pressure/manual for 12 minutes. Once done cooking, use the natural or quick release function and release the steam. Drain the potatoes well.2. Finish as directed above from step 2 on.
To Make Ahead: Prepare the casserole through step 3. Cover and store the assembled casserole in the fridge for up to 2 days. To bake, remove the casserole from the fridge while the oven preheats, then bake as directed.