Clean the meat, and trim off any excess fat. Generously sprinkle with salt and pepper. Heat a large pan until very hot. Add a tablespoon of canola or vegetable oil, and sear the meat, about 2 minutes on each side.

Place the sliced onions at the bottom of the slow cooker, and place the meat on top. Add the remaining vegetables (save a few scallion pieces for garnish). Mix all the sauce ingredients, except the sesame seeds, and pour over the meat. You can prepare ahead of time, up to this point, and keep it in the fridge.

Cover, and cook for about 3 to 4 hours on high or 5 to 6 hours on low. Flip over once midway through the process, if you’re home. Cook until the meat is tender but sliceable. Once cooked, remove the meat to a cutting board. Drop the reserved scallion pieces into the hot cooking liquid. Transfer the vegetables to a plate.

Thinly slice the meat against the grain. Run the sauce through a strainer, and pour over the meat and vegetables to serve.