Warm a large skillet over medium heat and pour in the olive oil.
Dry the salmon fillets using paper towels and sprinkle salt and pepper evenly on both sides.
Place the salmon fillets skin side down in the hot pan in a single layer, cooking each side for about 3 minutes until the fish is just done, then transfer them to a plate.
In the same skillet at medium heat, add the onion and garlic and stir frequently until the onion becomes translucent, around 3 minutes.
Sprinkle in the flour, continuously stirring for 2 minutes to cook it slightly.
Add the oregano, thyme, paprika, and crushed red pepper, mixing everything together quickly.
Pour in the milk and vegetable broth while stirring gently and let it cook for a couple of minutes to create a creamy base.
Once the sauce thickens slightly, stir in the sundried tomatoes, Manchego cheese, fresh basil, and lemon juice.
Return the salmon fillets to the skillet, placing them in a single layer, then reduce the heat to low and simmer for 2 to 3 minutes to warm the salmon through.
Serve right from the pan garnished with lemon wedges and a sprinkle of chopped parsley for a fresh finish.