Preheat the oven to 400ºF.
Combine all the dry ingredients in a bowl (flour, baking powder, baking soda, sugar, salt) and whisk.
Add the butter chunks and, using your fingers or a pastry blender, incorporate the butter until the pieces are no larger than a pea.
In a separate bowl, whisk together the egg yolks and heavy cream.
Form a well in the centre of the dry ingredients and pour the egg/cream mixture into the well.
Mix the dry and wet ingredients together using a wooden spoon or rubber spatula, mix the dry and wet ingredients together until a dough forms.
Divide the dough into 8 equal portions and "dip" each portion into the bowl of raw sugar, keeping the bottoms sugar-free so they don't burn during baking.
Place the 8 shortcakes onto a parchment-lined baking sheet and bake for 15 minutes, until the tops are golden brown.
Allow the shortcakes to cool completely while you prepare the berries.