In a bowl, combine the tahini, lemon juice, and a few splashes of hot sauce. Stir to combine. If the mixture thickens, add a few splashes of water and whisk until smooth.
Fry the leek:
Heat oil in a wide pot over medium-high. Melt the butter into the oil (if using). Once frothy, add the sliced leek and cook for 7-8 minutes until it softens and turns golden around the edges.
Add the garlic and minced chili or chili flakes. Cook for 45 seconds until fragrant. Add the thyme, paprika, and white pepper. Add a pinch of salt and toss to coat. Cook for 45 seconds.
Cook the chickpeas:
Add 4 cups of water or stock to the pot. Add the chickpeas and white parts of the scallions. Bring to a boil and then reduce heat to low. Add a big pinch of salt and simmer for 15–20 minutes until the chickpeas are very tender.
Cook the greens:
Add the greens and the remaining ¼ cup water and cook until the greens are bright green and tender, about 5–10 minutes, depending on the variety used.
Finish the broth:
Scoop out a spoonful of the hot broth, add it to the bowl of tahini, and stir until smooth.
Pour the tempered tahini mixture into the broth and stir until completely incorporated. Taste and season again to your preferences.
To serve:
Ladle the chickpeas into bowls. Garnish with chopped avocado and minced scallion greens. Sprinkle with Aleppo pepper and a drizzle of extra virgin olive oil, if desired. Enjoy!