• 12 ozs (340 g/2½ cups) flour
• 2 ozs (55 g/¼ cup) castor sugar
• a pinch of salt
• ½ teasp. bread soda
• 3 ozs (85 g/¾ stick) butter
• 1 egg (preferably free-range)
• egg wash
• 5½ fl ozs (165 ml/¾ cup) buttermilk or sour milk
• 1½ lbs (675 g) rhubarb, finely chopped
• 6–8 ozs (170–225 g/1¾ cup) granulated sugar
• castor sugar for sprinkling

1 × 10 inch (25.5 cm) Pyrex or enamel plate

Preheat the oven to 180°C/350°F/regulo 4.

Sieve into a bowl the flour, castor sugar, salt and bread soda; rub in the butter. Whisk the egg and mix with the buttermilk. Make a well in the centre of the dry ingredients. Pour in most of the liquid and mix to a soft but not sticky dough; add the remainder of the liquid if necessary.

Sprinkle a little flour on the work surface, turn out the dough and pat gently into a round. Divide into two pieces: one should be slightly larger than the other; keep the larger one for the lid. Meanwhile dip your fingers in flour. Spread the smaller piece onto the plate. Scatter the finely chopped rhubarb all over the base, egg-wash the edges and sprinkle the rhubarb with sugar. Roll out the other piece of dough until it is exactly the size to cover the plate, lift it on and press gently to seal the edges. Make a hole in the centre for the steam to escape, egg-wash and sprinkle with a very small amount of sugar.

Bake in a moderate oven, 180°C/350°F/regulo 4, for 45 minutes to 1 hour or until the rhubarb is soft and the crust is golden. Leave it to sit for 15–20 minutes so that the juice can soak into the crust. Sprinkle with castor sugar. Serve still warm with a bowl of softly whipped cream and some moist, brown sugar.