Sticky pineapple upside-down cake

Method

1. Heat the oven to 180°C/160°C fan/
gas 4. Put the butter and sugar in a food processor and whizz until smooth and creamy. Add the eggs one at a time and whizz to combine, then add the flour, ground spices, stem ginger (not the syrup) and milk and whizz until just combined. (If you don’t have a food processor, cream the butter and sugar in a mixing bowl with an electric hand mixer, then beat in the eggs one at a time, followed by the flour, ground spices, stem ginger and milk.)
2. Mix the stem ginger syrup, golden 
syrup and rum in a bowl. Put the pineapple wedges in a bowl, pour over half the syrup and toss (reserve the rest to serve). Arrange the pineapple in the prepared tin and spoon over any syrup left behind in the bowl. Tuck in the vanilla pod. Spoon the cake batter over the pineapple and smooth the top. Bake for 40-45 minutes until well risen and the cake 
feels springy to the touch.
3. Leave the cake in its tin to cool for 
5-10 minutes, then invert onto a serving plate or platter. Drizzle over the remaining syrup and serve warm with rum custard, 
if you like, or cool to serve later.