Combine the heavy cream, milk, pumpkin puree, vanilla syrup, and pumpkin pie spice in a jar.
Use a milk frother to blend the ingredients for one to two minutes until foamy. Place the lid on the jar and shake vigorously for two minutes until bubbles form.
Fill a glass with ice and add cold brew coffee, filling the glass around 2/3 of the way full.
Top with the pumpkin sweet cream.
Store leftover pumpkin sweet cream in the refrigerator.