Boil the kettle; if using an electric frother, also add your milk and start the frother

While the kettle is boiling (and milk frothing), add your protein powder (and any extras) to a mug. Then add enough boiling water to cover the protein powder.

Using your frother, mix up the protein powder with the boiling water; If you're using a handheld frother, you can add milk at this point and froth everything until completely mixed and frothy.

If using an electric frother, add the frothed milk to the latte. Then enjoy!