First make the pastry. Put 200g plain flour into a food processor, together with 170g cold butter,
cut into small pieces and process for 10 seconds, then add 75ml cold water and process again for
another 5 seconds or so, until the dough just comes together. Remove from the processor and kneed
gently into a ball. Place on a floured surface and roll out to an oval shape, about 16 x 18 inches
(40 x 46 cm approx). Roll up around the rolling pin and transfer to a greased baking sheet. Chill
for 20 minutes. For the filling, mix 50g sugar with 3 Tbs ground almonds and spread this over the pastry
to within 5 cm of the edge. Cut 500g plums in half, remove the stones and cut again into wedges and arrange
these over the sugar/almond mixture. Dot with 3 Tbs butter cut into small pieces and sprinkle 50g sugar
over the fruit. Gather up the edges of the dough to enclose the fruit and sprinkle another 30g sugar
over the pastry rim. Bake the galette in a 190°C oven for an hour, until the fruit is soft and the pastry
is golden brown. Remove from the oven and brush melted apricot or plum jam over to glaze.
Let cool before serving.