In a 3-qt. microwave-safe casserole with a lid combine
the water and the broth, whisk in the cornmeal, a little at a time, whisking to
eliminate any lumps, and stir in the minced sage and the garlic.
Microwave the mixture, covered, at high power (100%),
whisking every 3 minutes, for 10-12 minutes, or until it is thickened and the
liquid is absorbed. Let it stand, covered, for 2 minutes and discard the garlic.
Whisk in the Mascarpone, the
Parmesan, the parsley, the Tabasco, and salt to taste.
Pour the polenta into a serving dish, and garnish it with
the sage sprigs.