Preheat the oven to 400°F (200°C). Lightly grease or spray a rimmed baking sheet with oil to prevent sticking and ensure even browning.

Rinse the cod fillets under cold water and inspect them for any remaining bones. Pat the fish completely dry using paper towels to remove excess moisture, which allows the topping to adhere properly. Cut the fillets into serving portions and place them on the prepared baking sheet.

Place the Ritz crackers into a small mixing bowl and crush them using the bottom of a glass or the back of a spoon until coarse crumbs form. Add the smoked paprika, garlic powder, and salt to the crushed crackers, stirring to combine evenly.

In a separate small, microwave-safe bowl, add the butter and cover it loosely with wax paper. Melt the butter in the microwave for approximately 30 seconds on high power, or until fully liquefied.

Drizzle half of the melted butter evenly over the cod portions to help the topping adhere. Spoon the seasoned cracker mixture over each fillet, covering as much of the surface as possible. Gently press the topping to secure it. Drizzle the remaining butter over the top to ensure a crisp, golden finish.

Place the baking sheet on the center rack of the preheated oven. Bake for 18–20 minutes, or until the cod is opaque and flakes easily with a fork. The cracker topping should appear lightly browned and crisp.

Remove the cod from the oven and allow it to rest for 1–2 minutes. Squeeze fresh lemon juice over each portion immediately before serving to enhance the flavor and balance the buttery richness. Serve hot.