Heat oven to 220C/200C fan/gas 7.
Line a very large rectangular baking sheet
with baking parchment. Unravel the roll
of pastry and carefully lift on top. Sprinkle
over the ground almonds and scatter the
plums to make an even layer. Sprinkle
with the flaked almonds, then the sugar.
Bake for 18-20 mins until the pastry
is golden and the plums are tender.
Allow to stand for 10 mins to cool a
little, then sprinkle with a little more
sugar and serve.