Defrost the strawberries. Puree with 2 tbsp. sugar and 1 tbsp. lemon juice. Mix mascarpone, quark, 3-4 tablespoons sugar, 1 tablespoon lemon juice and advocaat until smooth.
Break the lady fingers into large pieces and divide half of them into six dessert glasses. Sprinkle each with 1 tbsp. coffee. Spread 2 tablespoons of mascarpone cream on each. Layer the remaining sponge cakes, coffee and cream in the same way and spread at least two tablespoons of mascarpone cream on each.
Chill for 2 hours. Decorate with strawberry puree and chocolate shavings.