Heat 1 tablespoon olive oil in a medium saucepan over medium-high heat. Add the celery and scallion whites and cook, stirring occasionally, until soft, 4 to 5 minutes. Add the garlic and 1 teaspoon each Cajun seasoning and brown sugar and cook, stirring, 30 seconds. Add the beans, tomatoes and 3/4 cup water; bring to a simmer and cook until the liquid is slightly reduced, 10 to 12 minutes. Stir in the kale and cook until tender, about 5 minutes. Add the scallion greens and a few dashes of hot sauce.
Meanwhile, mix the remaining 1 1/2 teaspoons each Cajun seasoning and brown sugar and sprinkle on the flesh side of each fish fillet. Heat 1/2 tablespoon olive oil in a large nonstick skillet over medium-high heat; add 2 fillets, seasoned-side down, and cook, undisturbed, until blackened on the bottom, 3 to 4 minutes. Carefully turn the fillets and cook until opaque, about 1 more minute. Transfer to plates. Repeat with the remaining 1/2 tablespoon olive oil and 2 fish fillets. Serve with the kale and lemon wedges.
Photograph by Christopher Testani
Recipe courtesy Food Network Magazine