1. Preheat your oven to 200°C/Fan 180°C/Gas 6. Peel the sweet potatoes and chop them into bite-sized chunks. Trim and peel the red onion, then slice into thin wedges. Halve the peppers, scoop out the seeds and white pith, then chop them into bite-sized pieces.
2. Spread all the veg out on a baking tray. Drizzle over a little oil and season with salt and pepper. Dust over the cumin, coriander, smoked paprika and dried oregano. Turn the veg to coat them in the seasoning. Slide into the oven. Roast for 30 mins till the veg are tender and lightly charred.
3. Meanwhile, beat the eggs in a mixing bowl with a pinch of salt and pepper. Drain the black beans and rinse them. Drain the halloumi and coarsely grate it. Add half the halloumi to the eggs and stir to mix well.
4. Grease an ovenproof frying pan and set it on a medium heat. Scoop in the tender roasted veg and add the black beans. Stir to mix. Pour in the beaten eggs, Scatter the remaining halloumi over the top. Fry for 3-4 mins, till just set underneath. Transfer the frying pan to the oven and bake for 20-25 mins till set underneath.
5. While the frittata bakes, halve the avocado and scoop out the stone. Scoop the flesh out of the skins and finely slice it. Finely slice 1-2 chillies, removing the seeds and white pith if you prefer less heat. Pick the leaves off a handful of coriander sprigs.
6. Serve the frittata in wedges, warm from the oven, garnished with the sliced avocado, chillies and coriander.
7. Get Ahead
You can roast the veg and store in an airtight tub in the fridge up to 3 days before you want to make the frittata. When you're ready to cook the frittata, add a the veg to the frying pan with 2 tbsp water and fry, stirring, for 2-3 mins to warm through. Then scoop to one side, drizzle in some oil to coat the base of the pan, and add the black beans. Continue, following the recipe.