Dice the chicken breasts and place them in a bag together with one tablespoon of vegetable oil, the granulated garlic, salt, pepper, paprika and cayenne pepper.
Seal the bag, give it a good shake to coat the chicken nicely, then transfer the chicken to the pan and grill on both sides until cooked through, it should takes about 5 minutes or so.
Meanwhile, peel and cut the onion and red peppers and break the broccoli into small florets.
I prefer the broccoli really tender, so I boiled it in salted water for 5 minutes, but you can skip it if you don't mind a bit of crunch.
Remove the chicken from the pan, add the remaining tablespoon of oil.
Fry the onion until tender, then add the peppers and broccoli and stir for 2-3 minutes.
Preheat the oven to 200 degrees C (390 Fahrenheit).
Cut the buns in half, arrange one layer of chicken, then top with the vegetables and grated cheese.
Bake for 8-10 minutes until the cheese has melted.
Garnish with fresh parsley and extra cheese if you like.