Carol Field's Crostini Piccanti

I’ve had Carol Field’s book Italy in Small Bites for years, but only recently did I start making this piquant topping for crostini. It has all my favorite assertive flavors: anchovy fillets, capers, olives, and vinegar. And it comes together easily in a food processor. The recipe calls for four hard-cooked egg yolks. Don’t toss the empty egg white halve…