Wash rice in cold water, drain, put on with 1/2 l water. Peel the onion, put the cloves in the onion, add to the rice.
Bring to a boil once with half the butter and a little salt, reduce heat and steam for about 25 minutes (according to package directions) until al dente.
Remove the onion, let the rice steam open for a short time, mix in the remaining butter and serve.