Put milk in a pot. Add starch and mix with a whisk. Add eggs, sugar and cinnamon and mix well. Cut the vanilla pod lengthwise and add it together with the cinnamon pod to the egg milk.
Heat over medium heat while stirring continuously and remove from the heat just before boiling. Continue stirring for 2-3 minutes. Pour cream through a sieve. Let it cool down while stirring occasionally.
In the meantime, drain the peaches. Cut peaches into slices and pat dry. Pluck the lemon balm leaves from the stalk and cut into narrow strips. Fold into the cooled cream.
Whip the cream until stiff and, except for about 4 teaspoons for decoration, fold in as well. Line dessert glasses with peach slices and fill in the cream. Serve with remaining cream, brittle and, if desired, decorated with lemon balm leaves.