Prepare all the ingredients and have them lined up in front of you in the order listed above.
Heat the oil in a large non-stick frying pan, add the onions and garlic, cover and cook for about 3 minutes until soft.
Then add the peppers and peas, stir in, cover again and cook for a few more minutes.
Make a well in the center, put the tomatoes in the well and the paprika on top.
Then add the stock (with the saffron if you have it), but make sure it doesn't overflow: If it gets more then half a cm close to the rim of the pan, stop adding stock and just use less rice.
Season with pepper and stir.
Scatter as much of the rice as you think will fit over the stock, stir it in gently, then allow it to simmer gently until the liquid has absorbed and the rice is cooked. This should take about 20 minutes, stirring occasionally.
Test a bit of the rice to see if it's cooked, add a bit of stock or hot water if it is not done.
Stir in the parsley a few minutes before it has finished cooking, if you want to use it, then serve hot.