Mashed Potatoes with Greens

Prepare in advance: Prepare according to this recipe by following step 4, and freeze. Defrost the potato mixture in the refrigerator at least 24 hours before you plan to serve, and let it simmer for 20 minutes before baking, as directed.
Melt 2 tablespoons butter in a large saucepan over medium-high heat. Add the cabbage and green onions; stir to coat. Add the stock; cover and cook, stirring frequently, for 10 minutes or until tender. Add salt and pepper to taste. Transfer to a bowl; cover to keep warm.Bring the potatoes, 1 tablespoon salt, and covered water to a boil in a saucepan over high heat. Reduce the heat to medium and simmer for 20 minutes or just until the potatoes are tender. Drain the potatoes and let them stand for 3 minutes or until they are completely dry. Return to the baking dish. Mash with a potato masher until smooth; add cream cheese and 4 tablespoons butter. Add the cabbage mixture.Heat the milk in a microwave-safe measuring cup over high heat for 1 to 2 minutes or until it warms up. Stir 1/2 cup of warm milk into the potato mixture. Add up to 1/2 cup more milk, 1 tbsp. l. Mix one at a time until the mixture thickens. (The mixture thickens as it cools) Season with salt and pepper.Transfer the mixture to a 2 1/2-inch thick greased baking dish. Brush with the remaining 2 tablespoons of butter. Cover the dish tightly with plastic wrap and then aluminum foil. Refrigerate for 8 hours to 5 days, or freeze for up to 2 weeks.Preheat the oven to 350 degrees. Remove the plastic wrap and foil and bake for 30 minutes or until fully warmed. Serve warm.COOKING TIPWhen there is enough room in the oven, reheat this mashed potato with butter in the microwave. Prepare the mashed potatoes in a microwave-safe bowl and heat them on high power in 1-minute increments, stirring each time, until tender. Then spoon them onto a serving platter.