Preheat the oven to 110C. Line a baking sheet with baking parchment.
Blitz the nuts in a mini chopper or chop into small pieces with a knife.
Put the egg whites and both sugars in a heatproof bowl over a saucepan of simmering water and heat for 5-10 minutes, until the sugar has totally dissolved (rub a little between your fingers - it shouldn't feel grainy). Remove from the pan and whisk with a hand whisk or pour into the bowl of a stand mixer and whisk on high for 6-8 minutes or until shiny and thick. Gently fold in the cinnamon.
Using two spoons, dollop blobs of meringue on your baking sheets. Sprinkle with the chopped nuts. Bake in the oven for an hour to an hour and 10 minutes (test - you should be able to lift them off the paper. Leave to cool in the oven, for an hour if you want the inside to be mallowy and until completely cold if you want a firmer texture all the way through (but still chewy in the middle).
The meringues keep well in an airtight tin for at least a week.
Eat on their own or with cream and fresh fruit / fruit compote. Blackberries, raspberries and peaches all work well.