1 very ripe, very cold avocado, halved and stoned
4 ounces red caviar
1/2 cup sour cream
1 egg yolk
1 teaspoon onion juice
Combine the last three ingredients to make the sauce. Spoon the caviar into the avocado halves, and over it the sauce. Serve ice cold with hot buttered Triscuits and lemon wedges.