1) Soak and soften gelatin in cold water.
2) Take a double boiler and combine mustard, eggs, salt, and sugar, in the top chamber.
3) Add vinegar and cream, cook over hot water until the mixture coat a silver spoon, ensure to stir constantly.
4) Add in gelatin and stir until gelatin dissolves.
5) Allow to cool and strain the custard over crab meat.
6) Take a mold and let it chill until firm.
7) Take a serving plate, unmold on crisp greens, garnish with tomato wedges, and serve.