Ingredients
For the sauce:
1 pound sweet Italian sausage (without fennel seeds)
1/3 cup extra virgin olive oil
2 medium onions, cut in half-moon slices (2 cups)
1/2 teaspoon salt
1/2 teaspoon dried peperoncino (hot red pepper flakes)
1/2 cup tomato paste
Boiling water from the pasta cooking pot
For the pasta and finishing:
1 tablespoon kosher salt, for the pasta cooking water
1 pound ziti
1/3 cup finely chopped fennel fronds
1 cup freshly Grana Padano
Preparation
Remove the sausage from its casing and break the meat up a bit with your fingers. Trim the fennel bulb. Slice the bulb in half lengthwise, then slice each half in 1/4-inch thick lengthwise slices. You will have about 3 cups of 2-inch long matchsticks of fennel. Pour the olive oil into the skillet over medium-high heat. Add the sausage meat and cook, stirring and breaking it up until it is sizzling and beginning to brown, about 1-2 minutes. Push the sausage a aside and drop the onion slices into a clear part of the pan; saute, stirring, till another 2 minutes will wilted. Clear another space in the pan. Drop in the fennel; let it heat up and wilt for 1 minute or more, then stir it with the sausage and onions. Sprinkle on 1/4 teaspoon salt; drop the peperoncino in a hot spot and toast the flakes for 1/2 minute, then stir them in. Clear a hot spot in the center of the pan, put in the tomato paste, and cook, stirring for a minute or more, until caramelized. Add 3 cups of boiling pasta water from the pot into the skillet, stir and bring the liquid to a boil. Adjust the heat to simmer. Cook ziti till right before al dente. Continue to simmer the sauce until the flavors have developed and the fennel is soft but not mushy, 6 minutes or more. The sauce should not get too thick: stir in another cup or two of boiling pasta water if it reduces rapidly. Drop ziti into the sauce pan. Start tossing pasta and sauce together; ladle in more water if the sauce seems too thick. Continue to cook and toss the ziti in the skillet for 2 minutes, or until they are perfectly al dente and coated with sauce. If the pasta appears dry, ladle in more hot pasta water; if it is soupy, cook rapidly to thicken sauce.
