Preheat your oven to 325 degrees F. Line your cake pan with aluminium foil and grease it, or grease your foil tray.
Put the butter, syrup, dark brown sugar, stout, ginger, cinnamon and ground cloves into a pan and melt gently over a low heat.
Take off the heat and whisk in the flour and baking soda. You will need to be patient and whisk thoroughly to get rid of any lumps.
Whisk the sour cream and eggs together in a measuring jug and then beat into the gingerbread mixture, whisking again to get a smooth batter.
Pour this into your cake/foil pan, and bake for about 45 minutes; when it's ready it will be gleamingly risen at the centre, and coming away from the pan at the sides.
Let the gingerbread cool before cutting into slices or squares.