Barbara Spiegel used dried cannellini beans when she came up with this creamy, smoky, herbal puree, but many plump, pale varieties will work. Long-soak, quick-soak, or pressure cook (my choice for consistency and speed) beans; or used canned ones if they are firm yet creamy, uniform in texture and unsalted, and taste like whichever bean they really are—not generic. Eden is the only brand I have found thus far that fits this description.
Spiegel noted that “these parsley leaves, once separated from the roots, kept almost forever—three weeks, that is—and had a peppery, cress-like edge.” Parsley root tops do vary: Some are more aromatic and nippy than others. She suggests serving the puree with duck breast, grilled lamb, or calf’s liver—in that order.