Sliced hard-boiled eggs and steamed asparagus, for serving
In a large bowl, combine 1/2 cup of the tomato juice with the gelatin; let stand for 5 minutes. In a saucepan, combine the remaining tomato juice with the sugar, salt, pickling spices, hot sauce, lemon zest and lemon juice and heat just until warm. Add the gelatin mixture and stir until it dissolves completely. Return the mixture to the bowl and refrigerate until cold but not set, about 1 hour.
Lightly oil eight 1/2-cup ramekins. Stir the onion, pepper and celery into the tomato aspic and spoon it into the ramekins. Refrigerate for at least 2 hours, until chilled and set.
Unmold the aspics onto plates and serve with sliced eggs and asparagus.