Bring the apricots, sugar, lemon zest and lemon juice to the boil, simmer for approx. 5 mins., allow to cool, roughly puree. Mix the mascarpone into the fruit puree. Beat the single cream with the icing sugar until stiff, fold in carefully. Transfer the mixture to a shallow container. Cover and freeze for approx. 4 hrs.
Bring the water and sugar to the boil in a stainless steel pan. Add the almonds, reduce the liquid on a medium heat, stirring constantly until the sugar is dry. Continue to stir until the sugar begins to melt again and forms a glossy coating over the almonds. Immediately spread the mixture onto a baking tray, leave to cool. Roughly chop.
Serve the ice cream, top with the almond croquant, decorate with lemon balm.