Purée?

Mash potatoes and a spinach sauce? You make mash potatoes as you usually do, as for the spinach sauce, you use around 250 grams of frozen chopped spinach, cook it in a little bit of water, about half a deciliter, and you add more if it's needed, when it cooks (there shouldn't be much water left at that point), you add a tablespoon or two of sour cream or greek yoghurt, and 1 deciliter of milk that you whisk a tablespoon of flour into just to thicken the sauce, stir a little on medium heat so it thickens, salt, and it's done. This usually makes enough for 2 people.