Creamy Polenta with Mushrooms

Name: Creamy Polenta with Mushrooms
Ingredients: 2 sprigs thyme; 2 sprigs rosemary; 1 sprig sage; 4 sprigs parsley; 1 large or two small garlic cloves, smashed and peeled; 1/2 teaspoon sea salt (truffle-infused salt if you've got it); 1/4 teaspoon coarsely crushed black peppercorns; 1/4 teaspoon coarsely crushed tricolor peppercorns; 3 cups water; 3 cups whole milk; 2 ears of corn, kernels removed (about 1 1/2 cup kernels); 1 1/2 cups polenta, preferably organic and coarsely ground; 1 cup dry white wine; 4 tablespoons truffle butter; 2 cups thickly sliced fresh mushrooms, a mix of shiitake and porcini; 1/2 cup mascarpone (and more for serving, if you wish); fresh baby spinach leaves for serving; parmiggiano