Ingredients:
* 175 g (6 oz) butter, softened
* 1 teaspoon lemon juice
* 4 red trout, about 250 g (8 oz) cleaned weight, heads and tails left on
* pepper
* dried fennel stalks, for cooking
* lemon wedges, to garnish
Fennel Mayonnaise:
* 3 egg yolks
* finely ground sea salt
* 300 ml (1/2 pint) olive oil, at room temperature
* 1-2 teaspoons tarragon vinegar
* 1 small bulb fresh fennel
* pepper