Heat the butter in a saucepan and add the onions with a pinch of salt. Cook, stirring, until it softened and begins to caramelize, about 5-7 minutes. Add the garlic and red bell pepper and cook for another 2-3 minutes. Mix in the mint. Then add the zest and juice of the lemon, as well as the coriander, and cook, stirring, for another 2-3 minutes.
Add the rice and the salt and cook the rice, stirring, for 3 minutes. Add the water and bring to a boil over high heat. When the rice is starting to boil, reduce the heat to the lowest setting and cover. Let it cook like this for 15-20 minutes, or until done. I had some extra liquid in my pan which I attributed to using a nonstick pot, so I boiled it off at the very end.