Step 1

Heat oven to 180C/fan 160C/gas 4 and put the kettle on. Butter and line a deep 20cm square cake tin. Sift the flour and spices into a bowl. Beat together the butter and sugar until light and fluffy in the food processor, then beat in the golden syrup. Dissolve the bicarbonate of soda in 200ml boiling water, then gradually pour through the spout of the processor. Pulse in the flour, then add the eggs, mixing briefly. Remove the bowl from the processor, then gently stir in the rhubarb.

Step 2

Pour the mixture into the tin and bake for 50-60 mins, until the cake feels firm to the touch and springs back when pressed. Cool in the tin for 5 mins, then turn out and cool on a wire rack. Dust with icing sugar.