Retro fish mousse

There's something rather 70s about using gelatine, and it's probably 30 years since I last did. This was a way to use up the end of the Christmas smoked salmon, although I think it would work with any kind of fish, fresh or smoked. (Actually, I don't yet know if it's "worked" because I haven't turned out the mould, but it looks and tastes good.) We've got some neighbours coming for supper in the kitchen tomorrow, and this seemed an elegant but not over-the-top way to begin.

Blitz 700g smoked salmon trimmings with a 500g tub of 0% fromage frais, and the juice & finely grated rind of a lemon. Meanwhile, soak in water two small sheets of gelatine (I used Costa fine leaf, bought in Waitrose), and heat 250ml fish stock. Take the stock off the heat, squeeze the gelatine and drop it into the stock. Stir to dissolve, then leave to cool. When it's cold but not set, mix it into the fish. This is enough for about eight people, so I put some into four little ramekins, the rest into a terrine mould lined with cling film. I'll freeze this and use it next week when we've got a few more people coming round.

I bought the fish stock, even though I normally try not to use industrially processed food. It was Waitrose Cooks' Ingredients, the sort that comes in a plastic bag. I read the ingredients list carefully, and decided to buy it because it had no salt, and contained only things that I use in my kitchen - white fish, lobster, langoustine, carrot, onion, white wine, tomato puree, celery, lemon juice, tarragon, bay leaf, white pepper. It doesn't say how much water there is - my guess is lots, because you would have been hard pressed to taste many if any of those flavours. Next time I'm at the fishmonger, I think I'll get some trimmings and make my own, so that I can freeze it in very small amounts.