Slice off top of the head of garlic. Take as little off as possible in order to have each individual clove exposed. Place garlic on aluminum foil, drizzle with olive oil and a pinch of salt. Wrap garlic in foil and put in preheated oven for 1 hour. Remove and set aside.
Add enough water to cover potatoes in a large pot and bring to a boil. Add a teaspoon of kosher salt to the water.
Cover and boil on medium heat for about 15 minutes. Potatoes should be somewhat resistant to being pierced by a fork or temperature probe.
Turn off heat and drain water off potatoes. Allow them to sit covered for additional 10 minutes. This allows the potatoes to finish cooking and dry out some. This step is crucial. After 10 minutes the potatoes should easily pierce with a fork.
In small saucepan, melt butter over low heat. When butter is melted add in the individual roasted garlic cloves and mash them in with a potato masher. Continue mashing garlic while adding the heavy cream. Once the butter, garlic, and cream are all mixed together and steaming (not boiling), add half the mixture to potatoes.
Mash the potatoes with roasted garlic butter mixture until completely incorporated before adding remaining half of mixture. Mash together and taste. At this point you are likely going to need to season with salt and pepper, but with mashed potatoes it’s important to mix, taste, season, and repeat as necessary in order to get the perfect amount of salt for your taste.
Serve potatoes and garlic with parsley garnish. Don’t be afraid to add a little extra butter to the top as they’re served.