Bring 6 quarts of water to a boil and add 2 tablespoons salt. Set up an ice bath next to the stovetop. Blanch the whole fennel bulbs in the boiling water for 10 to 12 minutes, until fork tender. Remove, refresh in the ice bath, drain and cut each bulb in half.
In a 14 to 16-inch, non-stick saute pan, heat the olive oil until smoking. Add the fennel halves, cut side down, and saute slowly until golden brown. Add the garlic and onions to the pan and turn the bulbs over. Mash the anchovies into a paste and add to the pan. Add the sambuca and swirl through the pan, cooking until the alcohol evaporates, about 1 minute. Remove the fennel bulbs from the saute pan to a decorative platter. Add the fronds to the remaining liquid in the pan, pour over the fennel and serve.
Recipe copyright 2000, Mario Batali. All Rights Reserved