Season the salmon lightly with salt and pepper on each side.
Cook your salmon however you would like - on the grill, in a skillet or in the oven. Cook about 5-6 minutes on each side until the internal temperature reaches 140-145F
To make the sauce, melt butter in a small saucepan. Add the garlic and cook for about 1 minute. Whisk in the flour until blended and smooth.
Gradually add the half and half and reduce heat to medium low. Stir in the Dijon mustard and dill. Salt and pepper to taste. Serve over salmon.