Heat up your pan on medium - hot heat. Add butter and garlic. Once garlic butter starts to sizzle, add your Brussel sprouts.
Turn down to medium heat and stir/shake the Brussel sprouts around in the pan until golden and slightly soft. This is a bit of a slow process and takes around 15 min to get them perfect. If you don't have the time to stand by the stove, then just caramelise for around 5 min until golden and pop into a hot oven for around 10 minutes to finish off cooking.