1. Preheat the oven to 120°C, gas mark ½. Line a baking sheet with baking parchment and draw a 25cm circle on it – use a dinner plate as a guide, then turn the paper over.
2. In a mini processor, whizz half of the rose petals with 100g caster sugar to a fine powder.
3. In a large bowl, whisk the egg whites and salt with an electric mixer to form stiff peaks. Whisk in the remaining caster sugar a spoonful at a time. Add the rose petal sugar in the same way. Whisk on full speed until you have a thick glossy meringue.
4. Spoon the meringue into the middle of the drawn circle, making a little indentation in the centre. Bake for 2-3 hours, then turn off the heat and leave the meringue in the oven to cool completely.
5. To make the syrup, put the ingredients into a pan and warm gently over a low heat until the sugar has dissolved. Bring to the boil and simmer for 5 minutes until thickened and syrupy. Strain to remove the cherries and set aside to cool.
6. Whisk the double cream with the icing sugar and kirsch, if using, until soft peaks form. Put the cooled meringue onto a serving plate. Spoon the cream on top and decorate with the summer fruits. Drizzle with the syrup and scatter with the remaining edible rose petals just before serving.