Pat the cod fillets dry with paper towels and season both sides evenly with the sea salt and black pepper.
Heat the ghee in a large cast-iron skillet over medium-high heat until it is melted and shimmering.
Carefully place the cod in the skillet and sear for 3 to 4 minutes until a golden crust forms, then flip and cook for another 3 minutes until the fish is opaque and flakes easily.
Remove the fish from the pan and set aside; in the same skillet, add the asparagus, halved cherry tomatoes, and minced garlic, sautéing for 3 minutes until the vegetables are crisp-tender.
In a small bowl, whisk together the Greek yogurt, lemon juice, and finely chopped fresh dill until the sauce is creamy and well combined.
Plate the cod over a bed of warm cooked quinoa, arrange the sautéed vegetables alongside, and finish with a generous dollop of the lemon-dill sauce.