In a large pot of salted water, bring the potatoes to a boil. Simmer for 20 minutes or until very tender. Drain completely. Return the pot of potatoes to the heat for a few seconds, stirring, to allow any excess water to evaporate.
With a potato masher, mash the potatoes until very fine. Add the cream cheese and continue mashing until the cream cheese is fully incorporated. Stir in enough of the cream to achieve a smooth, but still spoonable texture.
Stir in the roasted garlic pieces and cheddar cheese (if using). Season to taste with salt and pepper.
Spray a large baking dish with nonstick cooking spray. Preheat the oven to 350 degrees.
Spoon the mashed potatoes into the prepared dish. Dot the potatoes with the butter and bake for 30 minutes. Serve hot.
Notes
Promptly store leftovers in an airtight container in the refrigerator, for up to 3 days.Nutritional values are approximate and based on 1/12 the recipe.The casserole can be wrapped, chilled, and frozen before baking. To serve, thaw overnight in the refrigerator before proceeding with the baking step.Variations - Here are some things you can add to the casserole or sprinkle on top in the end: