With this recipe, we riffed on classic tonnato sauce (creamy tuna sauce) to create a dip for crunchy vegetables or as a sauce by tossing it with pasta. The egg yolk in this recipe is not cooked, but you can use a hard-boiled egg yolk instead or a yolk from a pasteurized egg. This recipe makes more cream sauce without the cream than you'll need for the dip. Refrigerate or freeze the extra sauce and use it in place of heavy cream in any sauce or soup that calls for cream.