Scrape out the pulp of the vanilla pod and bring to the boil together with the pod, lemon peel, 50 g sugar and water, simmer for 5 minutes. Let cool, remove the pod and lemon peel.
Whip the cream until stiff.
In another bowl, stir together the mascarpone, quark, 50 g sugar and lemon juice, fold in the cream.
In four tall glasses, alternate between cream, pear compote and choco crossies, possibly crushed, layer, finish with the cream and decorate with the crossies.