Preheat your oven to 400°F and line a baking sheet with parchment paper.
Spread the broccoli florets on the baking sheet, mist lightly with a small amount of avocado oil, sprinkle with 0.125 tsp sea salt, and roast for 15-18 minutes until tender-crisp.
In a small bowl, whisk together the Greek yogurt, Dijon mustard, lemon juice, capers, and chopped fresh parsley to create the remoulade.
In a shallow dish, combine the smoked paprika, dried thyme, onion powder, garlic powder, cayenne pepper, 0.25 tsp sea salt, and black pepper.
Pat the catfish fillets dry with a paper towel and coat both sides generously with the spice mixture, pressing it in to adhere.
Heat 1 tablespoon of avocado oil in a large cast-iron skillet over medium-high heat until shimmering.
Place the catfish fillets in the hot skillet and sear for 3-4 minutes per side until the crust is blackened and the fish flakes easily with a fork.
Plate the blackened catfish alongside the roasted broccoli and top with a generous dollop of the zesty remoulade.