Add rice to a large pan of boiling water and cook over high heat for about 15 minutes, or until just tender. Yes, I know this is not the norm for rice. You'll be cooking it in more water than it needs (like you would cook pasta). Drain, rinse under cold running water, and drain again thoroughly.
Heat 1 tablespoon of the butter in a heavy skillet over low heat. Add the rice, salt, and pepper and heat, stirring gently with a fork. Stir in the lemon juice, parsley, and capers and remove from heat.
Stir in the remaining butter and taste for seasoning. Serve immediately.