Holiday-Worthy Potato & Sweet Potato Mash with No Sugar | Bushwick Potato

Ingredients

• 1 1/2 pounds white potatoes – peeled and diced into 2-inch pieces
• 1 1/2 pound sweet potatoes – peeled and diced into 2-inch pieces
• 1 teaspoon salt
• 6 tablespoons butter – divided
• 2/3 cup warmed milk – divided
• Salt to taste
• Freshly ground pepper