1. In a bowl, stir together the shallot, green onion, mayonnaise, capers, dill and lemon juice. Season to taste with Cajun seasoning, salt and pepper and set aside.
2. In a bowl combine softened butter and barbecue sauce. Mix well to combine and set aside for basting.
3. To prepare the crab cakes in a large bowl combine crab meat, red, white and green onions, corn, mayonnaise and dijon mustard. With your hands, mix well and season to taste with salt and pepper. Gently fold in crackers and combine, being careful not to over mix. Pack crab meat into a small form, pressing excess air out of cake. Repeat with remaining crab mixture and set aside to rest.
4. To prepare the soft shell crabs brush with oil on all sides and season with salt and Cajun seasoning. Set aside.
5. Preheat grill to medium (about 400°F) on one side and to high (about 500°F) on the other.
6. Place crab cakes on a non-stick foil grill sheet over medium heat. Sprinkle with King of the Q Bayou Bite Cajun Seasoning. Close lid and grill-bake for about 12 to 15 minutes, moving them about so they dont stick, turning once and seasoning the other side with more King of the Q Bayou Bite Seasoning, until crisp and heated through.
7. Place seasoned soft shell crabs on grill over high heat and grill for 1 to 2 minutes. Turn over, baste with BBQ Butter, reduce heat to medium and grill for another 1 to 2 minutes, basting with extra BBQ Butter.
8. In a small bowl combine shredded lettuce, sliced red onion and dill. Mix well and set aside.
8. Remove crab cakes and soft shell crabs from grill.
9. To assemble the sandwich spread tartar sauce on bottom bun. Layer onion, dill and lettuce over top tartar sauce. Top with one crab cake, one grilled soft shell crab and top bun. Serve with extra tartar sauce and BBQ Butter for dipping.