Brew a strong cup of coffee using your preferred method, whether that's a drip machine, French press, or espresso. Let it cool to room temperature before using it, since hot coffee will melt your ice too quickly. This one step makes the biggest difference in getting that proper slushy texture everyone wants.
Pour the cooled coffee, milk, pumpkin puree, maple syrup, cinnamon, nutmeg, and vanilla extract into your blender. If you're using xanthan gum, add it now as well. Having everything measured out ahead of time makes this step go by fast and mess-free.
Add your ice cubes and blend on high speed until the mixture turns smooth and slushy, similar to the texture you'd get at a coffee shop. This usually takes about 30 to 45 seconds, but stop and check along the way so you don't over-blend it into liquid.
Pour your frappuccino into a tall glass right away while it's still nice and thick. Top it with a generous swirl of whipped cream and a light dusting of cinnamon for that classic finished look.
Grab a straw and enjoy your frappuccino right away. This drink is best served fresh since the ice will start melting and the texture will change the longer it sits out.