Place the mushrooms in a food processor fitted with a steel blade. Pulse until the mushrooms resemble couscous, about 10 pulses. Place minced mushroom in a large bowl. Place the quartered onions in the food process and pulse until minced. Add ¼ cup of the minced onions to the mushrooms and set the remaining onions aside for the sauce. There should be about ¾ cup of onions left.

Using your hands, mix the beef, garlic, cilantro, paprika, salt, and black pepper into the mushroom and onions. Roll into 1-inch balls. A 1-tablespoon cookie scoop speeds up this process and makes for uniform meatballs. You should have about 40 meatballs.

Heat a deep 12-inch skillet over medium-high. Working in batches so you don’t overcrowd the pan, brown the meatballs. Set the meatballs aside. Do not wipe pan out. The browned bits add flavour to the sauce.

Melt the butter in the meatball skillet over medium heat. Add the coriander, cumin, paprika, cinnamon, black pepper and chili flakes, if using. Fry for 30 seconds or until fragrant. Add the onion, ginger and garlic. Cook until the onion is translucent, about 5 minutes. Gently add the meatballs back into the pan. Add enough water to cover the meatballs by ⅔, about 1 cup. Bring the sauce to a boil, reduce to a simmer and cook with lid partially on for 40 minutes. Occasionally check to ensure the sauce hasn’t cooked down too far. You want about a cup of sauce left. Add more water if necessary.

Transfer to a warmed serving dish, sprinkle with fresh lemon juice and cilantro leaves. Serve with Middle Eastern flat bread to soak up the sauce. Alternatively, you can serve over couscous or rice.