In a large saucepan, melt the butter in the remaining 2 tablespoons of oil. Add the onion, shallot, garlic and rice and cook over moderate heat, stirring, until fragrant, 5 minutes. Add the wine and cook until it is absorbed. Add the vegetable stock, 1/2 cup at a time; stir constantly until it is absorbed before adding more. Cook until the rice is al dente, 20 minutes total.