Mix coffee and coffee liqueur. Line the bottom of a rectangular form (approx. 15 x 30 cm) with 100 g ladyfingers and sprinkle half of the mixture on top. Wash, clean and slice the strawberries. Spread half of the strawberry slices on the lady fingers. Stir sour cream with the whisk of the hand mixer for about 3 minutes until creamy, while pouring in the cream firming agent. Mix mascarpone, sugar and orange liqueur and fold in sour cream.
Spread half of the cream evenly on the strawberries. Cover with 100 g ladyfingers and sprinkle with the rest of the coffee. First spread the remaining strawberries on top, then the rest of the cream. Chill for at least 2 hours. Dust with cocoa before serving