Put the butter, flour and milk in a pan and cook, stirring over the heat until thickened. Stir in the cheese, in small spoonfuls, and the dill; season to taste, then beat to incorporate.
Heat oven to 200C/180C fan/gas
Butter 6 x 150ml souffl dishes and line the base with baking paper. Stir the egg yolks into the sauce, add the chopped salmon and lemon.
Whisk the egg whites until stiff, then carefully fold into the salmon mix. Spoon into the dishes and bake in a tin half-filled with cold water for 15 mins until risen and golden. Cool; dont worry if they sink.
To freeze, cool completely, then overwrap the dishes with baking paper and foil. They will keep in the freezer for 6 weeks. Thaw for 5 hrs in the fridge.
When ready to serve, very carefully turn the souffls out of their dishes, peel off the lining paper and place on squares of baking paper. Top with the crme frache and bake for 10-15 mins at 200C/180C fan/gas 6 until the souffls start to puff up. Quickly top each with a frill of salmon and a dill sprig.
Serve on their own or with some dressed salad leaves.
