Method

• 1.
  For pastry, pulse butter, flour and a pinch of salt in a processor until it resembles breadcrumbs. Add sour cream and pulse until dough comes together in a ball. Enclose in plastic wrap and chill for 20 minutes.

• 2.
  Meanwhile, place butter and caster sugar in a food processor and whiz for 5-6 minutes, stopping occasionally to scrape down sides of the bowl, until thick and pale. Add eggs, one at a time, whizzing well after each. Add the brandy and whiz for 1 minute to combine. Add flour and meal and pulse to combine. Set aside.
• 3.
  Line a large baking tray with baking paper. On a floured surface, roll out the pastry to a 30cm circle, about 5mm thick, and place on the tray or round pizza tray.
• 4.
  Spread almond meal mixture over tart base leaving a 5cm border. Arrange plums on top, cut-side down. Fold over the pastry edge to meet the filling and gently press down to seal. Chill for 20 minutes.
• 5.
  Preheat the oven to 190°C. Beat the egg yolk, milk and a pinch of salt together with a fork, then brush over the pastry edges. Bake for 40-45 minutes, until the pastry is golden and the plums are soft. Dust with caster sugar, cut into slices and serve.