Wash the sweetbreads, cover them with boiling water, and simmer 20 minutes. Plunge into ice water, and when cool enough to handle, break them up into smallish pieces. Sprinkle with tarragon vinegar. Make a chapon by rubbing the bread with the garlic cloves, and place the sweetbreads on top. Cover, and let stand several hours. When the chicken is cold, cut the meat into cubes. When ready to assemble the salad, remove the sweetbreads from the chapon and blend with the chicken. Grate the onion into the mixture, and add the Tabasco, soy, and salt. Add the almonds and lemon juice. Toss well. Whip the cream, and combine with the mayonnaise. Blend about half the dressing with the chicken. Arrange the salad on greens. Top with the remaining mayonnaise and garnish with black olives and pine nuts.