Add lemon juice to blender with sage; blend and add truffle oil in a slow drizzle. If too thick, add more lemon juice; if too thin, add more oil. (Olive oil is fine at this point but we generally use more truffle oil.) Season to taste and set aside.
Boil a pot of salted water and add raviolis. Cook until al dente, which should take no longer than 6–8 minutes.
In the meantime, heat a large saucepan and add butter and garlic. Do not allow either to brown. After about 2 minutes, add turnips and rabe, tossing them in the butter. Cook until softened but bright and not soggy. Season to taste. Add vinaigrette, stirring, so it emulsifies with the butter and makes a sauce. Add raviolis and toss so they absorb some of the sauce.
To serve, divide raviolis among 4 warm large, shallow bowls. Arrange them like a crown around rim with the vegetables in the center, reserving the sauce so you can pour it equally over each serving. Serves 4 as main course or 6 as a first course.
WINE PAIRING: 2012 Domaine de la Pepiere Cabernet Franc "La Pepie." This wine and the ethereal yet earthy qualities of the ravioli recipe are a match made in culinary heaven. It's a medium-bodied Cabernet Franc from the Loire Region of France with vibrant red fruits and flowers like violets and roses. Lurking underneath are haunting earthy flavors that couple with the mushroom ravioli and white truffle oil. – Eric Taylor, Bottles Fine Wine, Providence
Recipe by Allison Vanderburg, sous-chef, Cav, Providence, RI.