Leek and Mushroom Wild Rice

Name: Leek and Mushroom Wild Rice
Ingredients: 1 1/2 cups wild rice; 1 medium yellow onion, finely chopped; 6 leeks (white and light green parts only), halved, washed, and thinly sliced; 5 cups chopped mushrooms (a mixture, such as crimini, oyster or shitake); 4 cloves garlic, minced; 2 teaspoons finely chopped fresh rosemary; 2 teaspoons chopped fresh thyme leaves; grated zest of one lemon; juice from one lemon, about 1 tablespoon; 1/2 cup freshly grated parmigiano reggiano; 1/2 teaspoon freshly ground black pepper; kosher salt to taste; 2 tablespoons unsalted butter; 2 tablespoons extra virgin olive oil, divided; 1/3 cup dry sherry