Mix all ingredients above in bowl and let set at room temperature.
Take one slice of prosciutto and place on cutting board. Spread a dollop of filling from one side of the prosciutto to the other, widthwise (not lengthwise.) Place one spear of white asparagus on top of the filling with the tip emerging by 1/2 inch. Roll tightly and slice into 1-1/2 inch sushi-size pieces. Arrange on plate similar to a Japanese Maki roll.