Mix 275 ml cold water, flour and 1 pinch of salt with a whisk until smooth. Leave to swell for 15-20 minutes.
Drain the plums and collect the juice. Wash the lemon hot, dab dry and peel the peel thinly. Halve the lemon, squeeze one half. Boil up plum juice, sugar, cinnamon stick, lemon juice and peel.
Remove cinnamon stick and lemon peel. Stir starch with 3 tablespoons of water until smooth. Stir into the boiling juice. Simmer for about 2 minutes. Fold in plums, let them cool down.
Whip the cream until stiff. Fold into the dough in 2 portions. Heat up a waffle iron, grease with butter. Put about 2 tbsp. of dough in the middle of each wafer and bake about 16 golden brown wafers one after the other. Add the cinnamon compote.