Add the milk and whey protein isolate to a blender or shaker bottle.
Blend or shake until completely smooth and fully dissolved.
Refrigerate for at least one hour, and then whisk the milk to combine. (Optional but helps with texture)
Add the caramel syrup to taste to a cup and brew the espresso directly over the top, then stir to combine.
For an iced latte, add in the protein milk and ice. Stir once more to combine, and enjoy.
For a hot latte, steam the protein-boosted milk, then add to the caramel espresso mixture, and omit the ice.