Add the water, olive oil, and salt to a saucepan and let it come to a boil. Once it comes to a boil, stir in the rice, cover, reduce the heat to medium low and cook until the rice is fully cooked through.Then Allow the rice to cool for at least 20 minutes.
Cook the broccoli in boiling water for 3 minutes, then drain it and chop it into bite sized pieces.
Add about a tablespoon of olive oil to a skillet with high sides and add in the onions and cook for 2-3 minutes. Once the onions are softened, stir in the garlic and red pepper flakes. Cook for about 10 seconds.
Stir in the butter and once it melts completely, whisk in the flour. Cook it for 2-3 minutes while stirring frequently.
Slowly pour in the evaporated milk while whisking, then add the heavy cream. Cook the sauce for 15–20 minutes, or until thickened, stirring frequently to prevent burning or sticking.
Once the sauce is nicely thickened, turn off the heat and add 2 cups of cheddar cheese. Stir it well and then season with salt and pepper.
In a large bowl, combine the cooked rice, broccoli, and sauce, mixing until well incorporated. Transfer the mixture to a greased 9×9 baking dish, smooth the top, and sprinkle with the remaining cheese. Cover and bake at 350°F for 20 minutes.
Once the 20 minutes are up, uncover and bake for 3-5 minutes and broil until the top is golden brown.
Serve warm and enjoy!