Melt the butter in a saucepan. Let the sugar and oat flakes caramelize while stirring constantly. Then mix in the cinnamon. Pour the mixture onto a plate and let it cool down.
Whip the cream until stiff. Fill a bowl alternately with the applesauce and the cream (how much applesauce is up to you - some want more and some less). Scatter the oatmeal brittle on top and place the jam in the middle as a blob. Now chill for another hour.
You can of course enjoy this dessert straight away, but I personally like it better when chilled.