Prickly pear with mascarpone cream and roast pistachio

 Puree the peeled prickly pears in a food processor. Sieve over a bowl and separate juice from seeds, discarding the latter. Place the puree in a saucepan with 50g of castor sugar and bring to the boil, stirring. Once boiling, turn down to a bubbling simmer until the liquid has reduced by half. Let it cool and refrigerate. Meanwhile beat the egg whites in a bowl, slowly adding the rest of the castor sugar until firm peaks form. To this add the mascarpone and fold in until the resulting mixture is light and fluffy. To serve, ladle some prickly pear puree into bowls, add a large dollop of mascarpone cream and scatter some chopped, roasted pistachios on top. Finish by dusting with ground cinnamon.