There is no salt in this recipe, you will need to add salt when you decide to use it for making a sauce. To thicken 2.5 dl of liquid you will need to use 2 tbs of butter melted and 1 tbs of flour to make a rue. Add 250 ml of lobster stock and cook gently for 15 minutes and you should be fine. Season with salt and pepper.
You can finish the sauce by adding a tbs of cream to enrich the sauce. You really don’t need more.