Combine the rice and water in a saucepan and bring to a boil. Cover, reduce heat to low, and simmer until rice is tender and water is absorbed. Set aside to cool.
Melt the butter in a large skillet over medium-high heat. Add onion and garlic; cook and stir until fragrant and lightly browned. Stir in rice and cook until coated and heated through. Remove from the heat and stir in the lemon juice.