Pat the catfish fillets completely dry with paper towels to ensure a crispy sear.
In a small bowl, combine the smoked paprika, garlic powder, onion powder, cayenne, thyme, oregano, sea salt, and black pepper.
Evenly coat both sides of the catfish fillets with the spice rub, pressing gently so the seasoning adheres.
Heat the avocado oil in a large cast-iron skillet over medium-high heat until it begins to shimmer.
Carefully place the fillets in the hot skillet and cook for 3 to 4 minutes per side until the crust is blackened and the fish flakes easily with a fork.
While the fish cooks, steam the broccoli florets until tender-crisp and vibrant green.
Plate the blackened catfish alongside the cooked quinoa and steamed broccoli, finishing with a fresh squeeze of lemon.