Preheat the oven to 220°C (200°C fan) and prepare your ingredients.
Spread out the sweet potatoes, broccoli and chickpeas on a large baking tray and toss together with sumac, olive oil, salt and pepper.
Roast for 20 minutes, flipping the sweet potatoes over and tossing everything half way through cooking.
To make the dressing, combine the tahini, lemon juice, a dash of extra sumac, and a big pinch of salt in a small bowl and whisk until smooth. Thin with a little water, then stir through the mint.
To serve, divide the veggies between the bowls and drizzle with the tahini dressing.