- Bring to a boil 2 cups stock, basil, lemon grass, lemon, and chile, then steep, covered, about 20 minutes.
- Strain through a coffee filter.
- Meanwhile sprinkle gelatin on remaining 1 cup cool stock; let stand 1 minute, add to strained stock mixture, then heat, stirring until gelatin just dissolves.
- Pour into a 9" x 12" pan; chill to set.
- Reserve; then cut into small dice just before service.
- Mix crab meat with vinegar and soy sauce.
- Crosswise, thinly slice each avocado half, keeping slices for each avocado together.
- Line each of 12 small round molds or bowls (about 1 cup and 4 inches in diameter) with plastic film.
- Then line each mold with 1 sliced avocado, overlapping slices starting at centers of the bowls.
- Divide crab mixture among them, packing meat in.
- Per order, unmold 1 salad.
- Scatter about ¼ cup diced gelatin around mold.
- Season avocado with drops of lemon oil, coarse salt, and freshly ground pepper.
- Garnish with lemon slices and fresh basil.