In a small bowl, stir together matcha powder and about 1 tablespoon of warm water until dissolved.
Add milk, cream, vanilla syrup, and dissolved matcha powder to a mason jar and shake to combine. Alternatively, you can stir all ingredients together in a bowl. If you're not using right away, keep in an airtight container in the fridge. You can use this matcha sweet cream as is if you want.
Turn mixture into cold foam right before using. You can either use an electric frother, hand mixer, or blender. Just add half the matcha sweet cream and froth, mix, or blend until the mixture turns into a foam. Alternatively, you can shake the mixture in a mason jar until it's frothy.