1) Preheat the oven to 200°C/gas mark 6.
2) In the bowl of an electric mixer fitted with a paddle attachment, combine flour, sugar, bicarbonate of soda and salt. Blend in the cold butter at the lowest speed and mix until the butter is in pea-sized pieces.
3) Combine the eggs and double cream and quickly add them to the flour and butter mixture. Combine until just blended. Toss the strawberries with the 1 tbsp of flour, add them to the dough, and mix quickly. The dough may be a bit sticky.
4) Dump the dough out onto a well-floured surface and be sure it is well combined. Flour your hands and a rolling pin and roll the dough 2cm thick. You should see lumps of butter in the dough. Cut into squares with a 10cm plain or fluted cutter, then cut them in half diagonally to make triangles. Place on a baking tray lined with baking paper.
5) Brush the tops with the egg wash. Sprinkle with sugar and bake for 20 to 25 mins, until the outsides are crisp and the insides are fully baked.
6) Serve warm or leave to cool.