You can most easily make this with an instant hot chocolate mix, but if you like going that extra mile, make it yourself. Try this recipe by Ina Garten. I've made it countless times and though it can be a bit rich, it's worth trying at least once. At least.
If you decide to start from scratch and want to make Ina's hot chocolate, this is how to best give it a pumpkin-y kick. Add a cup of pumpkin puree, a teaspoon of cinnamon, 1/2 teaspoon of nutmeg, and 1/8 teaspoon of all spice to your hot chocolate mixture. Blend it together thoroughly before serving.
If you'd prefer a simpler by-the-cup route, however, here are your instructions. Prepare your hot chocolate as you normally would, then do one of two things. You can add just a dash of pumpkin flavor with some pumpkin pie spice and a little cinnamon. But if you're hardcore like I am, to your cup of already prepared hot chocolate add a tablespoon of pumpkin puree, and dashes of cinnamon, nutmeg, and all spice. Mix together thoroughly, then top with whipped cream and a little more pumpkin pie spice.
In my opinion the best whipped cream is homemade. I know it's not a shared thought, but if you're interested in giving it a try it's not difficult and only takes a few minutes. With your mixer, whip a pint of heavy whipping cream while slowly adding a cup of sugar. Continue to whip until semi-stiff peaks form. Voila! You're done! If you want a more flavorful whipped cream, add a teaspoon of vanilla. Trust me and just add the vanilla.
Enjoy your weekend friends! I'll see you all in October...with a cup of pumpkin hot chocolate in hand.