Heat the oil in a large pan, add the onion and a pinch of salt and cook on very low for 10 minutes - stirring every couple of minutes. Cooking them this long will make them very soft and sweet. Add in the peppers and carrots, cumin and paprika, give it a stir and cook for a further couple of minutes.
Add in the stock then place a metal sieve in the stock. Fill the sieve with the quinoa so it cooks separately from the veg. Bring to a boil and simmer for 20 minutes.
Whilst the soup is simmering, preheat the oven to 220c/425f.
After 20 minutes, take the soup off the heat, lift out the quinoa and place in a bowl. Blend the soup using a stick blender, then stir in the quinoa. Add in the 3/4 of the cheese and a good pinch of salt and pepper and stir until the cheese has melted.
Ladle the soup out in bowls, top with the crushed grissini and sprinkle with the reserved cheese. Place in the hot oven for 5 minutes to melt and brown the cheese.
Serve sprinkled with chopped chives (and caution your soup-eaters that the bowls will be very hot!)