Preheat the oven to 400 degrees F.
Butter a baking sheet. Lightly brush the fish fillets with olive oil and lightly bake about 15 minutes until half cooked. Mince and set aside to cool. (The fish may be broiled or grilled.)
In a medium saucepan over medium heat, melt the butter and 2 tablespoons oil. Stir in the green onion, bell pepper and celery. Sauté for 1 minute. Whisk in the flour and simmer for 1 minute. Whisk in the half and half and bring just to a boil, whisking continuously.
Remove from the heat, add the mustard, chili sauce and lemon juice and whisk vigorously to combine the flavors. Cool, then stir in the cooked fish. Refrigerate to firm. Process the pecans, bread and pepper in a food processor to make crumbs. Form the fish into 12 cakes. Coat with the pecan crumbs and place on the baking sheet. Drizzle with melted butter. Bake for 10 minutes until the crumbs are browned and the cakes cooked through.