– .8 lb russet potatoes (about 1 large), peeled & cut into 1 inch cubes – 1.6 lbs yellow potatoes (about 4 large), peeled & cut into 1 inch cubes – 1/2 cup salted butter, sliced into pats – 1 1/2 tsp kosher salt – 1 tsp Italian seasoning – 1 1/2 tsp garlic powder, (sub with 4 cloves minced garlic if desired) – 1/2 tsp freshly cracked black pepper – 1/2 cup milk (1%, 2%, or whole) – 1/3 cup heavy cream – 1/4 cup sour cream