Place the butter in a saucepan and heat over a medium flame. The butter will melt. Listen carefully and the butter will start hissing and cracking and forming little brown bits at the bottom of the pan. You want to wait until the noises start to subside, the butter smells toasty and is turning a darker colour. Remove from the heat as soon as it gets to this stage so it doesn’t begin to burn. Pour the butter into a heatproof container and set aside to cool for 5 minutes, you don’t want it too hot when you add to the rest of the ingredients.