Rinse rice under cold water until runoff is mostly clear to remove surface starch. Use a 1:1.25–1.5 rice-to-water ratio for most long-grain white rices (for example, 1 cup rice to 1.25–1.5 cups water). Bring water and rice to a gentle boil, add a pinch of salt and a teaspoon of oil or butter if desired.
Reduce to the lowest heat, cover tightly, and simmer undisturbed for 15–18 minutes. Turn off heat and let sit, covered, for 10 minutes to steam and finish cooking.
After resting, fluff with a fork to separate grains. Adjust water slightly next time if rice is too sticky (less water) or too dry (more water).