Preheat the oven to 350C/gas mark 4. Butter a 9-inch square baking tin and line the bottom with some baking paper, leaving an overhang to lift the cake out with.
Whisk together all of the dry ingredients in a bowl to combine well.
Whisk all of the wet ingredients together.
Make a well in the middle of the dry ingredients and add the wet. Whisk everything together just until smooth. Do not beat. Pour into the prepared baking tin.
Bake for 25 to 30 minutes, until a toothpick inserted in the center comes out lean and the top spring back when lightly touched.
Leave to cool completely in the tin.
Cut into squares to serve. Whipped cream or ice cream go very well.
