Preheat oven to 400°F. Lightly oil a baking dish with the olive oil.
Pat the cod dry and place in the dish. Drizzle with lemon juice, then season with salt, pepper, and paprika.
Combine crushed crackers, melted butter, garlic, parsley, lemon zest, and Dijon in a bowl until the crumbs are evenly moistened.
Press the buttery crumb mixture onto the tops of the cod pieces, dividing evenly.
Bake until the fish flakes easily and reaches 145°F, about 12–15 minutes depending on thickness.
Broil 1–2 minutes to brown the topping, watching closely. Rest 2 minutes before serving.