1/4 cup extra-virgin olive oil
12 sweet Italian sausages
3 fennel bulbs—trimmed, each bulb cut into 8 wedges, fronds chopped
1 medium onion, chopped
4 garlic cloves, minced
1/2 teaspoon fennel seeds, crushed
Kosher salt, to taste
One 28-ounce can San Marzano whole tomatoes, crushed ,juices reserved
1 cup dry white wine
3 pequin chiles or 2 chiles de árbol or crushed red pepper flakes
1/4 teaspoon sugar (optional)
Creamy polenta, for serving
In a large enameled cast-iron casserole, heat the olive oil. Add half of the sausages and cook over moderate heat, turning, until browned all over, 5 minutes. Transfer to a plate; repeat with the remaining sausages.
Add the fennel wedges to the casserole and cook over moderate heat, stirring, until golden, about 5 minutes. Add the onion, garlic, fennel seeds and 1 teaspoon of salt and cook, stirring, until the fennel is lightly browned, about 3 minutes.
Add the tomatoes and their juices, the wine, chiles and sugar. Tuck the sausages into the sauce. Cover and cook over low heat for 15 minutes.Uncover and simmer until the sausages are cooked through and the sauce is thickened, about 45 minutes longer.
Garnish the stew with fennel fronds and serve over polenta.
The stewed sausages can be refrigerated for up to 2 days; rewarm before serving.
Small, spicy dried red Mexican pequin chiles are available at Latin American markets and specialty food stores.
If pequin or arbol chile peppers are not available in y0ur area, crushed red pepper flakes will also do as a substitute for the dried chile peppers