3/4 lb. sweet Italian sausage (about 4 links), casings removed
1 large russet potato, peeled and cut into large dice (about 2 cups)
1 medium red onion, cut into large dice
1 small fennel bulb, trimmed, cored, and cut into large dice (about 2 cups), plus 1 to 2 Tbs. chopped fennel fronds for garnish
3 Tbs. dry sherry
4 cups lower-salt chicken broth
1/4 cup chopped fresh flat-leaf
1/4 cup chopped oil-packed sun-dried tomatoes, drained
2 Tbs. heavy cream
1 tsp. finely grated lemon zest
Kosher salt and freshly ground black pepper
Heat the oil in a 4-quart saucepan over medium-high heat. Add the sausage and cook, stirring with a wooden spatula to break it up into small pieces, until it starts to brown, about 3 minutes. Stir in the potato, onion, and fennel and cook, stirring occasionally, until the onion begins to soften, about 2 minutes. Add the sherry and stir, scraping the bottom of the pot to loosen any browned bits, about 30 seconds.
Stir in the chicken broth and bring to a boil over high heat. Reduce the heat and simmer until the potatoes are tender when pierced with a fork, 10 to 12 minutes.
Add the parsley, sun-dried tomatoes, heavy cream, and lemon zest and stir until incorporated.
Using the spatula or a potato masher, gently crush the cooked potatoes until most of them are mashed and the stew is somewhat thickened. Season with 1 tsp. salt and 1/2 tsp. pepper. Serve hot, garnished with the fennel fronds.