Place all ingredients except bread in food processor. Purée. Hold in refrigerator to stiffen before packing for picnic.
At the picnic, serve spread on slices of crusty bread. If desired, top each slice with scallions, prosciutto, anchovies, roasted red peppers or cooked bacon.
*Roasted red peppers from a jar may be substituted.
** Sourdough bread may be substituted.