Begin by preparing the anchovies. To butterfly the fish, remove the heads and slice each anchovy open along its belly. Rinse the cavity carefully to remove any residual entrails and blood, then push down skin-side up on a chopping board and push down firmly to loosen the spine

Carefully peel away the skeleton from each fish, then rinse the fillets thoroughly under cold running water and drain well

To make the marinade, mix together the lemon juice, white wine vinegar and salt until fully emulsified. Pour the marinade into a bowl or large tray, then add the anchovies to the tray skin-side up. Cover with cling film and leave to marinate for 20–30 minutes, until the flesh turns a lighter colour

To serve, drain the anchovies well and arrange the fillets across a serving platter or plate. Drizzle over a little olive oil and garnish with the fennel fronds, chopped chilli and a generous grinding of pepper