For the pavlovas: whisk the egg whites with the sugar, salt, lemon juice and cinnamon until stiff. Fill into a piping bag and pipe 10 pavlovas onto a baking tray lined with baking paper. Bake in the preheated oven for approx. 90 minutes.
For the mousse: whisk the unchilled QimiQ Classic smooth. Add the mascarpone, plum puree and sugar and mix well. Fold in the whipped cream and fill into a piping bag.
Cut off the tips of the pavlovas and press a small hollow into the middle. Pipe the cream onto the bases and top with the cut off tips.