Simple, quick, reliable (as long as you respect the proportions to the letter, otherwise it won't unmould properly, but will merely collapse dispiritedly onto the plate!)...on its own, this mousse is perfectly serviceable, but a little one-note-ish; with the addition of a chilled tarragon sauce, though, it is lifted to a whole other level. The original for the mousse came from Evelyn Lauder's rather alarmingly day-glo pink 'In Great Taste'...which actually has a number of good things inside, if you can make it past the front cover.
For four individual mousses:
Ingredients: 450g Salmon Fillet; 2 sprigs of Dill; 8g powdered gelatine; quarter cup of tomato puree; 2/3 cup of Sour Cream (or creme fraiche); 1/2 cup plain Yoghurt; half a medium onion; zest and juice of a medium lemon; seasoning. For the sauce: 1 cup of fish stock (from powder is fine); half a cup of white wine; half a cup of cream; a handful of finely chopped tarragon.
1. With a sharp knife, remove the skin from the salmon, then cover the fish with water in a shallow pan, add the dill, and poach gently for about six minutes until cooked through. Remove the fish, to cool, and discard the poaching liquid and dill.
2. Add the gelatine to about 50 ml warm water in a simmertopf, or a bain marie, and stir whilst dissolving over medium heat.
3. Put all of the ingredients (apart from those for the sauce) into a food processor and blend throughly. Adjust seasoning as appropriate. Then divide the mixture between four ramekins, and chill in the fridge until set - probably four hours or so (or longer, if you want to be on the safe side).
4. Combine all of the sauce ingredients, apart from the tarragon, in a small saucepan and reduce over medium heat for fifteen or twenty minutes until the consistency is like thick cream. Taste for seasoning and adjust as necessary (you won't need any if using commercially made stock), and stir in the sauce the chopped tarragon. Allow to chill.
Unmould onto cold dishes, and spoon the sauce over the top to serve.