Frangipane is very adaptable - it can be spread in a shortcrust pastry base, as here, or in a galette or jalousie of puff pastry. Most fruits go well with it, and I have made variations with plum, apple, apricots, figs, and more. Today's version has the shortcrust pastry case spread with rhubarb jam and chunks of rhubarb baked in orange zest and sugar, then topped with the frangipane mixture, which is simplicity itself to make: 100g each of soft unsalted butter, ground almonds and caster sugar, 2 eggs and the zest of an orange. Mix for a minute or two in an electric mixer until creamy and well combined. If it is very loose, add up to 25g of flour, but no more - you want it to be moist and almondy rather than too 'cakey'. Carefully dollop and spread over the jam and rhubarb, sprinkle with flaked almonds, and bake at 170C (fan) or the equivalent for 40 mins until golden brown and the pastry is golden and crisp. Serve just warm with cream or, in our case, custard. Enjoy!