Ingredients:

  • 1 lb Russet potatoes, peeled and cubed
  • 1 lb Yukon Gold potatoes, peeled and cubed
  • 1 tsp salt (for boiling water)
  • 1/2 cup unsalted butter
  • 1/2 cup whole milk
  • 1/4 cup sour cream
  • 3 cloves garlic, minced
  • 1 1/2 cups sharp cheddar cheese, freshly grated
  • 1/4 cup parmesan cheese, finely grated
  • 1/2 tsp salt
  • 1/4 tsp black pepper

Instructions:

  1. Place cubed potatoes in a pot and cover with cold water. Add 1 tsp salt. Note: Salting the water seasons the potato from the inside out.
  2. Bring to a boil, then reduce to a simmer and cook until fork tender, typically 15-20 minutes.
  3. Drain the potatoes thoroughly in a colander.
  4. Return them to the hot pot for 60 seconds over low heat, shaking gently until the excess moisture evaporates and they look steamy.
  5. Pass the potatoes through a ricer or mash vigorously until smooth.
  6. Stir in the melted butter and minced garlic until the mixture is fragrant and glossy.
  7. Stir in the warm milk and sour cream. Note: Warming the milk prevents the mash from cooling down too quickly.
  8. Gently fold in the grated cheddar and parmesan until the cheese is fully incorporated and the mash is a uniform consistency.
  9. Season with 1/2 tsp salt and 1/4 tsp black pepper.