A traditional "yaptchik" - just like my Bubbie used to make. No beans, no barley, nothing fancy - just potatoes, onions and meat. Because really, what more do you need? Note that you can use a food processor on the potatoes if you are pressed for time, but for an authentic taste and texture you really need to hand-grate them. It goes a lot faster than you'd think (especially if you get your kids to do it for you!) and is well worth the effort.
4-5 lb potatoes, peeled and grated
2 large Spanish onions
1-2 lb flanken (I use the kind with bones but without works, too)
2 tsp salt, or to taste
½ tsp pepper, or to taste
In a large bowl, mix the grated potatoes, onions, salt and pepper.
Layer half the potato-onion mix in the bottom of the slow cooker.
Lay the flanken over the bottom layer of potato-onion mix.
Cover with the remaining potato-onion mix. DO NOT ADD ANY WATER. (I didn't believe my Bubbie either the first time I made this, but trust us, it will be plenty juicy.)
Cook on high for at least a couple of hours, then turn down to low before Shabbat. Enjoy!