Make the shortcakes first: Preheat the oven to 200C/400F and line a large baking tray with grease proof paper/a silicone mat/a Silpat.
Place the flour, baking powder, bicarb, salt, white sugar and cubed butter into a large bowl.
Rub the butter into the flour until you have a mixture which resembles coarse breadcrumbs. Some slightly large lumps of butter are fine.
Place the cream and egg into a jug and beat lightly, then pour 2/3 of it into your flour mixture.
Start to bring the mixture together with a fork, mixing gently and coaxing it into a soft dough. Add the remaining cream mixture a little at a time until your dough just comes together. You don’t want any lumps of flour not incorporated, but you don’t want a very soft, sticky dough. It needs to hold, but not be like a cookie dough!
Half the dough, then half it again and then again until you have 8 balls of dough.
Roughly shape them into a ball (these look better the more “rustic” they are) and then place 2 inches apart on your lined baking tray.
If desired, brush the tops with egg and sprinkle a little light brown sugar on the top of each shortcake. This step is not imperative, but does give you gorgeously golden, glossy shortcakes.
Place in the oven for 10-12 minutes, until risen, golden and they sound hollow when you tap them. They should still feel a little soft underneath the top, but not so soft they feel raw.
Leave to cool completely on the tray.
Whilst they are cooling, make the caramel apple filling: Place sliced apples, caramel sauce, spices and cream into a medium sized saucepan and place over a medium heat. Bring to a boil, stirring frequently and then cook until the caramel sauce darkens, becomes thicker and the apples are tender, 7-9 minutes. Leave to cool. (The caramel mixture will thicken more as it cools).
Whilst the apple mixture is cooling, make the whipped cream filling: Place cream, vanilla extract and sifted icing sugar into a large bowl and whisk until soft peaks form. You want it to hold a peak and be spreadable, but not so stiff you could stand a spoon in.
When the shortcakes are cooled completely, slice them in half horizontally and then divide the apple mixture between the 8 shortcakes, spooning it into the centre of each shortcake base.
Top the apple mixture with a dollop of whipped cream and spread gently just to ensure you have a pretty level layer of cream.
Top with the shortcake tops and dust with icing sugar, if desired.
Caramel Apple Shortcakes are best served on the day of being made, but you can make all the components without assembling the shortcakes, then keep them in airtight containers in the fridge overnight. Bring to room temperature before assembling and serving the shortcakes!