Preheat your oven to 390 degrees, then clean and dry your potatoes
Use a fork to poke holes into your potatoes so that moisture can vent while baking. Then put the half cup of kosher salt down onto a baking sheet (optional). Place the potatoes on top of the salt and bake for one hour or until a knife can enter and exit the potato with no resistance. (It is important the potatoes are completely done for uniform mashing)
Remove the potatoes from the oven and allow them to cool to a temperature safe to handle.
Place a sauce pan on the stove over low heat and add the milk, cream, butter, peppercorns, bay leaves, Thyme, and Parsley Stems. Once the butter has melted, reduce the heat to a simmer and allow the ingredient to steep for 20-30 minutes. (This is about transferring flavor, not cooking the dairy products. DO NOT cook the dairy products)
Once cool enough to handle, slice your potatoes in half and use a spoon to remove everything but the peel to a large bowl. (Keep the skins to eat when no one is looking)
Slowly add the liquid to the potatoes while using a hand masher or electric mixer. Let the potatoes absorb all the liquid before adding more, then repeat the process until you have reached your desired consistency of mashed potatoes.
Mix in the garlic powder, some salt, some pepper, and anything else you'd like... like more butter. Garnish with chopped parsley leaves and serve warm.