Rinse fennel thoroughly; trim and reserve fronds. Mince fronds, reserving 1 tablespoon. Trim tough outer leaves and discard. Cut bulb in half lengthwise, and discard core. Cut bulb crosswise into 1/4-inch slices; set aside.
Heat olive oil in a Dutch oven over medium heat; add fennel slices, and sauté 5 minutes. Stir in broth and next 5 ingredients; bring to a boil over high heat. Cover, reduce heat, and simmer 15 minutes. Stir in peas and reserved fennel fronds; cover and simmer 2 minutes.
Ladle 1 1/4 cups stew into each of 4 bowls; top with Parmesan Polenta Rounds, and sprinkle evenly with cheese.