Step #1
Place the sliced rhubarb and gin into a bowl and soak for at least 4 hours or overnight. Place the water, oil and cake mix into a bowl and beat for 1-2 minutes to form a smooth batter.
Step #2
Drain the rhubarb and reserve the gin. Add the rhubarb and stem ginger to the cake batter and mix well.
Step #3
Pour into a well greased pre lined 23cm (9inch) square cake tin. Rub the butter into the 75g of cake mix. (Don’t worry if this starts to stick together)
Step #4
Mix in the porridge oats breaking any lumps of cake mixture. Scatter the oat topping on top of the cake batter.
Step #5
Bake in a preheated oven 190°C (375°F) gas mark 5 for 40-45 minutes until firm to the touch.
Step #6
Skewer the cake and drizzle over the reserved gin. Leave in the tin to cool before turning out.