Mashed Potatoes with Ham with spinach

2 lbs cubed yukon gold potatoes 2 tablespoons extra virgin olive oil 1/2 teaspoon salt 1/4 teaspoon fresh ground black pepper 1/4 cup 2% low-fat milk 4 cups[...]

4 (6 ounce) bags fresh baby spinach 4 lbs white potatoes , peeled and cut into 2 inch pieces 1/2 cup butter (do not use margarine) 1 1/4 cups warm whole milk[...]

6 -8 cups water 1 -2 teaspoon salt 2 1/2-3 lbs baking potatoes , peeled and cut into large cubes 4 ounces butter , melted 1 medium onion , sliced (optional) 2[...]