Start by pre-heating your oven to 170c/325f. Also grease and line a 9x12 inch cake tin with some baking paper.

In a large bowl, add the butter, oil, sugar and vanilla. You want to beat these ingredients together, using an electric or stand mixer, on high speed for 5 minutes. You can also make this by hand, just beat for as long as you can.

Add 3 of your eggs into this, whisk until smooth, then whisk in the remaining eggs.

Now add in half the flour and whisk this in. Add in the milk, whisk, then add the rest of the flour. Whisk just until you get a smooth batter.

Pour this batter into your prepared baking tin and bake this for around 45-55 minutes, or until a toothpick inserted into the centre comes out clean.

Once baked, leave to cool down.

Pre-heat your oven again, to 170c/350f.

Once the cake has cooled, cut it into strips. You can cut these to whatever length you want, just make sure they're around 1.5-2cm thick.

Place these onto a large tray that has been lined with baking paper.

Bake these for around 25-30 minutes, or until golden brown. Then flip them, and bake them until this side is golden brown too. I've noticed that this baking time varies a lot, they might need less time or they might need longer. Just keep an eye on them, you just want them to be a golden brown colour on both sides.

Once baked, leave them on the tray to crisp up for 10 minutes and then you are done!