Cut up two chicken breasts and sauté in olive oil+butter. Add pepper during sauteing. The point is to scorch the outside for flavor without cooking the inside much. Place chicken in slow cooker/crockpot.
Chop four medium potatoes in smallish pieces and add to cooker.
Slice eight medium leeks (I hope you already know to wash away any dirt and discard the tough green parts) and add to pot.
Add one can/tin of Cream of Mushroom soup. I don't care that it's cheating. It turns out great.
Top with spices and stuff: about a tablespoon each of tarragon, dried chopped onion and chicken bouillon granules; a sprinkle of celery seed; a teaspoon or so of ground mustard powder; and ground black pepper to taste.
Pour hot water over all of it until it comes up to within an inch of the solid ingredients. Stir it all up somewhat.
Cook on low for 6 or 7 hours. Or start on high for an hour and then turn it down for 5 hours. Whatever. As long as the potatoes are tender, you're good.