6 medium potatoes, (about 4 pounds) peeled and cubed
3 cups whole milk
1/2 cup heavy whipping cream
2 tablespoons unsalted butter
1 garlic clove, minced
1-1/4 teaspoons kosher salt
1 teaspoon coarsely ground pepper
1/2 teaspoon seasoned salt
6 green onions, thinly sliced
Shredded cheddar cheese and crumbled bacon, optional
Place potatoes in a large stockpot or Dutch oven; cover with cold water. Bring to a boil. Cook, uncovered until very tender, about 20-25 minutes; drain well, reserving 1 cup liquid.
Return potatoes to stockpot or Dutch oven; mash until desired consistency. Return pan to heat and add milk, heavy cream, butter, garlic and seasonings; heat on medium-low until heated through, 5-10 minutes, adding reserved cooking liquid to thin soup to desired consistency. Serve warm. Top with green onions. If desired, sprinkle with cheese and bacon.