Make the pumpkin syrup by combining brown sugar, pumpkin puree, pie spice, and water in a small saucepan. Stir and warm on the stove until sugar is melted and dissolved. Remove from heat to cool. You can pour into a heat-proof container and pop in the fridge or freezer to cool down faster. You can also double or triple the syrup depending on how much sweetness you like or to use throughout the week. 

Make the foam by blending together the half and half, evaporated milk, and pumpkin syrup using either a frother, immersion blender or French press (see recipe notes). Depending on your desired sweetness you can increase or decrease syrup to your liking. 

Divide the cold brew into 4 glasses. Top each with the sweetened cold foam.