Line a large baking tray with baking paper and set aside. In a large bowl, combine the flours, baking powder and sugar. Stir them well to combine.
Add the butter pieces to the flour and rub the flour into the mixture. Keep going until the mixture looks a little sandy. There should be no huge chunks of butter but it shouldn’t be entirely dissolved or incorporated. Little sheets of butter are what we’re after. If it’s summer and your butter starts melting, pop the mixture in the fridge for 5-10 minutes.
Add the whisked egg and use a spoon to gently incorporate it.
Add the cream, 1/4 cup at a time. Gently push the mixture around to combine without being too rough or flattening in the pieces of butter. The dough should be a little bit shaggy but all the loose bits of flour should be wet or attached to the main ball of dough. There should be no dry or crumbly flour. You might not need all the cream; assess as you go.
Gather the dough into a ball in the bowl and cover. Place in the fridge for 15-20 minutes to firm up.
Flour a clean, dry surface with tapioca flour. Place the chilled dough onto the surface, and use a rolling pin or your hands to create a rectangle of dough, about 3 centimetres thick. Keep moving the dough and making sure it isn’t sticking. Add tapioca flour whenever necessary.
Use your scone cutter to cut out the cobbler bits, flouring it liberally and whenever necessary. Place the cut scones onto the lined baking tray, and continue until you have used all the dough. Depending on the size of your cutter, you should have 18-24 little scone bits. I like to place them in the freezer for a little while to set the butter and encourage lift in the oven but the fridge is fine too.
Preheat the oven to 200C/400F.