Preheat the oven to 170°C fan.
If you’re using a food processor, pulse the butter and flour together until the mix resembles fine breadcrumbs. If using your hands, use a knife to cut the butter into the pastry, then use your fingertips to 'rub in' the butter. Now add the sugar and pulse or stir. Then add the egg yolk and water. Pulse or work until a dough forms, don’t over mix. Wrap and chill for 30 minutes.
On a lightly floured surface, roll out the pastry larger than the tin itself. Line the case and trim the excess pastry from the sides. No need to bake this blind. Pop into the fridge while you make the frangipane.
For the frangipane, cream the butter and sugar in a freestanding mixer or with an electric hand whisk until really light and fluffy. Gradually mix in the egg, then fold in the ground almonds and flour. Spread in the chilled pastry case.
Cut the elderberry poached pears in half lengthways and remove the core. I use a melon baller for this, it’s the perfect tool for the job. Slice finely, lengthways and arrange on top of the frangipane. sprinkle the flaked almonds on the frangipane. Bake on 170°C for 40 minutes, then reduce the heat to 160 °C and bake for a further 10 minutes. Serve warm. Take some of the syrup from your poached pears and brush it on the baked pears so they're nice and glossy. Dust with icing sugar and serve with ice-cream of cream.