Ginger Cake
Sift together the flour, baking powder, spices, and salt.
In a medium pot, melt the butter along with the golden syrup, treacle, brown sugar, and 75ml of the milk. Bring to a slow boil.
Whisk in the baking soda (be careful as it will bubble up quite a bit!) and then the rest of the milk to cool it down. Let it sit for 10 minutes.
Whisk in the flour mixture, followed by the beaten egg, stem ginger and syrup.
Let the mixture sit for 2 hours at room temperature. Meanwhile, grease and line the tin(s) with parchment paper.
Preheat the oven to 160°C (140°C fan). Stir the cake mixture and pour into the prepared tin(s).
Bake in the preheated oven for an hour, or until the cake is firm to the touch.
Spiced Poached Pears
In a medium saucepan, place the sugar, water and all of the spices. Bring to a simmer.
Peel the pears (leave the stems intact) and place in the spiced liquid. Simmer for about 2 hours - or until soft.
Leave in the solution while it cools, and store in the liquid until you are ready to serve.
Caramel Sauce
In a small pot, make a dry caramel with the sugar. If you're not comfortable making a dry caramel, use water to get the sugar dissolving, then simmer until it turns a dark amber.
Warm the double cream in the microwave until steaming. Once the caramel is a dark amber, add the cream, and whisk together.
Boil the solution until it reads 107°C, then remove from the heat. Whisk in a pinch of salt, and some vanilla (optional).
German Buttercream
In a small pot, add the milk, half the sugar, and the vanilla bean. Bring to a simmer and remove from the heat. Let infuse for at least 30 minutes.
In a small bowl, whisk the egg yolk with the cornstarch and sugar. Add enough milk to make a slurry.
Bring the milk back to a simmer, and slowly whisk into the egg mixture. Return to the pot and bring to a boil (whisking constantly).
Boil the mixture for at least 10 seconds, and then pass through a sieve. Stir in the 7g butter, then press cling film to the pastry cream to prevent it forming a skin. Cool to room temperature.
Whip the butter in a medium bowl until light and fluffy. Add the pastry cream a spoonful at a time, whipping well in between.
Cake Assembly
Place one of the ginger cake layers on your cake plate, and top with a third of the buttercream. Place the second layer on top, cover with another third of the buttercream, and then use the rest to ice the sides.
Spread some of the caramel sauce on top, allowing small drips to go over the sides.
Remove the poached pears from the liquid, and pat dry with some paper towel. Arrange on top of the cake, and surround with some candied nuts.