Put the liver, egg, garlic, oil and baking powder in a food processor, whizz until it is a smooth paste. Add the flour gradually until the mixture resembles a sponge cake mix, add more or less flour if needed. Pour out onto a baking tray. Bake at 180oC in the oven for about 20 mins, test with a skewer and if it comes out clean, its ready. Cut into training size cubes when cool. Freeze and defrost and use as required. Notes: If you use Self Raising flour you get a crumblier result. I often add a grated carrot. You'll see when cutting it up it sort of separates into a cakey top and bottom with a meaty middle. Have fun cleaning out the food processor - its a bit yucky and this recipe doesn't suit those with a weak stomach!!