Prepare the Sauce:

In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté until it's fragrant but not browned.
Sprinkle in the flour and cook for a minute to remove the raw flour taste, stirring constantly.
Gradually add the white wine, stirring continuously to prevent lumps. Once the wine is incorporated, add the fish stock and bring the mixture to a simmer.

Cook the Hake and Clams:

Season the hake fillets with salt and pepper, then nestle them into the skillet. Cover the skillet and let the hake cook for about 5 minutes.
Add the clams to the skillet, distributing them around the hake. Cover again and cook until the clams open and the hake is cooked through, about 5 to 7 more minutes. Discard any clams that do not open.

Finish the Sauce:

Sprinkle the fresh parsley over the fish and clams, gently stirring the sauce without breaking the fish fillets. Adjust seasoning with salt and pepper if necessary.

Serve:

Serve the hake and clams with plenty of the green sauce. Offer lemon wedges on the side for squeezing over the dish.