Pat the salmon fillets dry with paper towels. Using a sharp knife, cut a deep pocket into the side of each fillet, making sure not to slice all the way through the bottom.
Add the chopped spinach, Greek yogurt, parmesan, garlic, salt, and pepper to a bowl. Mix until the filling becomes creamy and well combined.
Spoon the spinach-parmesan filling into each salmon pocket. Press gently to seal the fillets around the mixture; it’s fine if a little filling shows.
In a small bowl, combine the paprika, garlic powder, onion powder, cayenne, oregano, salt, and pepper. Rub this seasoning generously over the tops and sides of the salmon fillets.
Heat an oven-safe skillet over medium-high heat and add a drizzle of olive oil. When the oil is hot and shimmering, place the salmon in the pan with the seasoning-side down. Sear for 2–3 minutes until a dark, flavorful crust forms, then flip and sear the other side for 1 minute.
Transfer the skillet to a preheated 400°F (205°C) oven and bake for 8–10 minutes, or until the salmon reaches 125–130°F internally and flakes easily with a fork.
Let the salmon rest for about 3 minutes before cutting or serving. This helps keep the fillets tender and juicy.
Serve the stuffed salmon with your favorite vegetables, grain bowls, salads, or healthy sides of choice. Store any leftovers in airtight containers for easy meal prep.