Put the butter in the freezer for approximately 15 minutes. Preheat oven to 375 degrees.
Wash and dry berries. Cut strawberries into quarters or smaller depending on the size. Zest and juice one lemon.
In a bowl or container add sugar and 1 tablespoon lemon juice. Top with mixture of berries. Do not stir until approximately 1 hour or less before eating.
In a large bowl mix together flour, 1/4 cup sugar, baking powder, salt and lemon zest.
With a cheese grater on large section grate very cold butter - for measuring you will need 85 g. Stir the butter into the flour mixture with a fork.
In a small bowl whisk an egg. Add 1/2 cup cream and 2 tablespoons cold water and whisk again.
Slowly add liquid to dry ingredients and mix with a fork. DO NOT OVERMIX.
Transfer dough to a lightly floured surface and pat into a square about 2 cm thick.
Cut out 8 rounds using a cookie cutter or glass approximately 6-7 cm across. All rounds should be the same size so they bake evenly.
Place on parchment lined baking sheet. In a small bowl whisk together egg yolk and 1 tablespoon cream, using a pastry brush paint egg mixture over tops of shortcakes and sprinkle with white or coarse sugar.
Bake in the centre of the oven until golden brown approximately 20-25 minutes and cool on wire racks.
Whip cream with an electric mixer or by hand with a whisk - slowly adding icing sugar when soft peaks form continuing mixing until firm peaks form.
To assemble, cut shortcakes in half through the middle using a bread knife. Divide among plates. Put berries on the bottom half, add a dollop of whipped cream and then top with the upper halves of the biscuits and serve.