4 large baking potatoes
1 large leek - white and light green parts only
1 small/medium head savoy cabbage
4 Tbsp butter*
1/2 to 1 cup half-and half or milk*
salt to taste
Peel baking potatoes. Cut into rough 1 -2 inch chunks. Place in large pot, cover with water. Bring to boil. reduce heat and simmer 15 minutes, or 'til tender. (Insert fork into potato chunk. if there is any resistance, continue cooking.)
While potatoes are cooking, Cut leek in lengthwise quarters. Slice crosswise very thinly.
Cut Savoy Cabbage in half lengthwise. Remove core. Cut each half lengthwise into 4-6 pieces. Slice crosswise very thinly. (You're going for something close to a chiffonade, but not quite that thin.)
In large, deep skillet, melt butter over medium heat. Add leek. Cook, stirring, 'til leek is translucent and beginning to soften. Add cabbage. Stir and cook with leek til very tender, probably 15 minutes. Reduce heat if anything starts to brown.
Using a slotted spoon, remove still warm potatoes to a colander. Reserve liquid in pot in which potatoes cooked. Put potatoes through a potato ricer into a large bowl. (If you don't have a ricer, a masher will do, but won't produce quite the same texture.) Add half cup half-and-half or milk. and whisk. If potatoes seem too stiff, add more dairy, up to one cup.
To potato mixture, add the leeks and cabbage, using a spatula to get all the butter. Stir thoroughly to mix completely. Add salt to taste.
*If you are vegan, or concerned about fat content, you may substitute vegetable oil for the butter, and use the liquid from the cooking pot instead of the dairy. The texture of the dish will be different, but it will still be very tasty.