Meanwhile, heat the butter and olive oil in a medium pot over medium heat. Add the garlic and saute until golden, 1 minute. Add the mushrooms, onions and 1 teaspoon sea salt and saute for 8 minutes. Stir in the rice and cook for 2 minutes. Deglaze with thewine and cook until the wine has reduced completely. Ladle in the simmering broth, 1/2 cup at a time, stirring constantly until the rice absorbs all the broth before adding more. Repeat until all the brothhas been added and the rice is al dente, about 20 minutes. Stir in the cheeses and a pinch of sea salt and pepper.