Cook the orecchiette according to the package directions.
About a minute or two before the pasta is cooked, stir in the chopped broccoli rabe. Before draining the pasta and broccoli rabe, reserve 1 ½ cups of the cooking liquid.
If you place a measuring cup in the colander set in your sink, it will serve as a reminder to reserve the cooking liquid.
After reserving the 1½ cups of cooking liquid, drain the pasta and broccoli rabe.
Return the drained pasta and broccoli rabe to the empty pot and set on the stove, but don’t turn on the burner under it. Heat the olive oil in a medium skillet over medium heat.
Add the garlic, salt and pepper to taste, the crushed red pepper flakes and the fennel seeds. Cook for about 2 minutes, stirring until just golden brown but not burned.
Add the Caravella Limoncello and the reserved cooking liquid. Cook at a low-medium boil, stirring occasionally for 1 minute.
Turn the garlic mixture into the pot of pasta and broccoli rabe and stir to combine.
Scatter the slices of butter over the top and stir to mix well until the butter melts and the sauce looks creamy. Add salt and pepper to taste. Serves 4-6.