Soak the gelatine in cold water. Put the sugar into a pan and heat slowly until caramelised. Stir in the cherry juice and orange juice and add the cherries. Mix the cornflour to a smooth paste with cold water, stir into the cherries and juice and boil up once. Divide the cherries between 6-8 small jars and leave to cool.
Squeeze out the gelatine. Whip the cream until very stiff and chill. Beat the egg yolks with the icing sugar and grated orange rind over a hot bain-marie until pale, thick and creamy. Stir in the squeezed-out gelatine. Pick the flowers off two sprigs of lavender and chop finely. Add the lavender flowers and mascarpone to the egg yolk mixture, a spoonful at a time, then fold in the whipped cream.
Break the sponge fingers into 2 or 3 pieces and scatter on top of the cherries. Mix the espresso with the coffee liqueur and honey and drizzle over the sponge fingers. Put the mascarpone cream into a piping bag with a plain nozzle and pipe on to the sponge fingers.
Chill the tiramisu for at least 2-3 hours. Shortly before serving sprinkle with the rest of the lavender flowers. Serve garnished with a sprig of lavender.