In a medium bowl, combine heavy whipping cream, sweetened condensed milk, and vanilla extract. Whisk until well combined and the mixture is slightly thickened, usually about 2-3 minutes.
Gently stir in the pumpkin puree and pumpkin pie spice. Continue whisking until the mixture is smooth and creamy, with no lumps remaining.
Cover the bowl with plastic wrap and refrigerate for at least 30 minutes.
Brew your favorite cold brew coffee and pour 8 ounces over a glass filled with ice.
Remove the chilled pumpkin mixture from the refrigerator and blend it briefly with a hand mixer or whisk until the foam is light and fluffy, about 1-2 minutes.
Carefully spoon the whipped pumpkin cold foam over your cold brew coffee. For an extra touch, sprinkle with additional pumpkin pie spice on top.
Notes
Store leftover foam in an airtight container for up to three days, re-whipping before use for best texture.