Smoky, spicy blackened fish was made famous by New Orleans' Paul Prudhomme. This simple version boosts caramelization with the addition of brown sugar, so you can use a bit less heat (which means less smoke in your kitchen) but still get the signature crunchy crust. Add a beans-and-greens side dish that gets kick from Louisiana green hot sauce and you have a super-flavorful meal ready in about 30 minutes.
Heat 1 tablespoon 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 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 oil and 2 fish fillets. Serve with the kale and lemon wedges.