Pour hot coffee into a mug. Add vanilla simple syrup. Mix well.
Froth soy milk. If you don't have a milk frother you can mix the soy milk in a blender* or shake it in mason jar with a secure lid and towel over the top.
Pour soy milk over coffee. Spoon foam on top.
Notes
*Vanilla beans and extract can vary in strength. Adjust the amount to your tastes.*Do NOT put hot soy milk in a Nutribullet! If you want to use a Nutribullet, you'll need to blend cold soy milk because it doesn't do well with hot liquids.