Heat oven to 200C/180C fan/gas 6.
Put the breadcrumbs, olives, parsley,
mint, lemon zest, anchovies and garlic
in a food processor, and blitz until
everything is roughly chopped. Tip into
a bowl and stir through the pine nuts,
sultanas, chilli flakes (if using) and a good
grinding of black pepper. Arrange the
fennel slices in a small roasting dish and
drizzle with a little olive oil.
Working methodically, lay each fish
fillet, skin-side down, on your work
surface, cover with some of the crumb
mixture, then drizzle ½ tsp olive oil over
each. Roll up the fillets, leaving the tails
sticking up. Use a cocktail stick to secure,
then stuff a little more of the crumb
mixture into the sides.
Arrange the rolled-up sardines on
the fennel, scatter over the remaining
crumb mixture, then pop the slices
of lemon and bay leaves in the gaps.
Drizzle with the remaining olive oil and
season with sea salt and pepper. Bake
in the oven for 20 mins until the fish is
cooked through and the crumbs are
golden and crisp in places. Serve
scattered with the fennel fronds.