Break up 4 sponge fingers and drop into 4 large wine glasses.

Cut 5 strawberries into thick slices and set aside. Put the rest into a bowl and crush to a rough pulp with a fork. Add sweetener to taste and the balsamic vinegar. Mix together and spoon over the sponge biscuits

Reserve about 10 raspberries for decoration and roughly crush the rest with a fork. Beat the yogurt until smooth and add the crushed raspberries, plus a little sweetener to taste if liked. Fold gently together as a ripple effect then spoon over the strawberries.

Top with the sliced strawberries and raspberries. Halve the remaining sponge fingers and stick in the top of the glasses. Decorate with the little herb sprigs and chill lightly before serving.