Heat a large skillet over medium to medium-high heat. Add the olive oil.

Once hot, add the onion and a couple pinches of salt and pepper, and sauté for three to four minutes. Then add the garlic and ginger and sauté for an additional one to two minutes.

Add to a slow cooker. Add the sweet potatoes, chickpeas, fire-roasted tomatoes, three tablespoons of the tahini, silan, vegetable broth, salt, and ras el hanout. Stir to combine. Cook on high for four to five hours, or on low for six to seven hours. Turn off the slow cooker and let the stew cool for 10 minutes or so.

Stir in lemon juice and the remaining tablespoon of tahini, and season to taste with additional salt and freshly cracked black pepper.