We bought a leek and had some potatoes. After reading various pros/cons about ingredients, I thinly sliced the leek (rinsing after each cup full just in case), 4 small potatoes (1:1 ratio, maybe slightly more potato), and added those with a small handful (2T?) of sea salt with enough water to cover +2" into the crock pot. Set at high for 3 hours (the same amount of time the roast needed to be done). Unplugged the crock pot and plugged in the hand blender; pureed the whole thing. It was beautiful. 3 ingredients, 4 if you include water.
No need for extra pepper, or anything else for that matter. Not even bread.
Hot, warming, soothing. Perfect even as a midnight snack.