This lemon butter sauce is the most traditional sauce for grilled salmon and really easy to make too.
To be fair it's not just a sauce for grilled salmon, it works well with a sea trout steak and you can use it with any grilled white fish too. Not only does it compliment the fish flavors it's also looks great, almost like a clear glaze.
Do take care to follow the method instructions carefully and don't be tempted to try and work too fast. If you do you'll end up with a split sauce and have to start again. If you don't know what I mean by splitting, you will if it happens. What you are looking for here is a nice thick emulsion, not something that looks like a load of granules swimming in melted butter. When it comes to this recipe, patience is a virtue.
The quantity that I've made below is enough to cover about 4 fish portions.
TIP - I prefer to use white or grey pepper from a shaker for this recipe because freshly ground black pepper leaves black specks in the sauce and doesn't look great from a presentation point of view.
240gr or 8oz unsalted butter - cut into cubes, then used straight from the fridge
5 tablespoons vegetable stock
1 level teaspoon cornflour, dissolved in a little cold water
Pour the lemon juice and vegetable stock into a small saucepan, add the salt and pepper and boil until it has reduced in volume by two thirds. Now remove from the heat.
Chop your butter up into small cubes and add them one at a time and whisk. Don't add the next cube until the prior one has fully melted and whisked in.
When you've used about half the butter, return the saucepan to gentle heat, continue whisking and adding the butter cube by cube until it's all gone. Finally add the cornflour liquid a dash at a time to get a nice thick consistency.
The cornflour also helps ensure that the sauce doesn't split before serving.