Heat the olive oil in a large, heavy skillet over medium-high heat. Add the onions, celery, and bell peppers, and cook, stirring, until soft, about 3 minutes. Remove from the heat and let cool.
Combine the mayonnaise, a little at a time, with the cooked vegetables, 1/2 cup plus 2 tablespoons of the bread crumbs, and 1 tablespoon of the Essence in a large bowl, and mix well. Gently fold in the crabmeat.
Combine the flour with 1 1/2 teaspoons of the Essence in a shallow bowl and mix well. Combine the remaining 1 cup of bread crumbs with the remaining 1 1/2 teaspoons of Essence in another bowl. Whisk 1 egg with the milk in another bowl.
Using your hands, form mini cakes with the crabmeat mixture, packing gently but firmly. Dredge each crab cake in the flour mixture, then in the egg wash, then the bread crumb mixture, shaking to remove any excess breading.
Heat 1/2 cup of vegetable oil in a large, heavy skillet over medium heat. Pan-fry the crab cakes 3 or 4 at a time until golden brown, about 4 1/2 minutes per side. Drain on paper towels.
To serve, arrange the crab cakes on a platter and top each with a spoonful of the relish. Serve hot.
Yield: about 20 cakes