For shortcrust pastry, combine flour, sugar and butter in a food processor and pulse until mixture resembles coarse breadcrumbs. Add egg and 1-2 tbsp cold water and pulse until pastry just comes together, then form pastry into a flat disc, wrap in plastic wrap and refrigerate for 30 minutes.
Whisk eggs and sugar until pale and frothy and mixture has doubled in size. Fold through lemon rind, almond meal and cinnamon.
Preheat oven to 180C. Roll out pastry on a lightly floured work surface to 3mm thick. Line a 25cm-diameter tart tin with pastry, trim edges and prick base with a fork. Spoon almond mixture into tart tin and smooth top. Bake for 50 minutes or until golden. Cool tart in pan, then remove from pan and serve dusted with icing sugar.