Heat oven to 200C/180C fan/gas 6.
Slash the trout's skin three times on both
sides then stuff a thyme branch into each
cut. Lay the fish on a baking sheet and fill
the cavity with the lemon slices and
remaining thyme sprigs. Season the fish,
drizzle over some olive oil then bake it for
15-20 mins until cooked through.
Meanwhile, mix lemon juice with olive
oil, then pour over the fennel and allow to
stand for 10 mins. Stir in the radishes and
capers and season. Mix the rocket through
the fennel and radish salad just before
serving with big bits of the flaked trout.