Start by adding brown sugar, pumpkin pie spice, and water to a saucepan on low-medium heat.
Whisk to combine and bring to a very low simmer.
Once the sugar has dissolved, take the pan off of the heat.
Pour the syrup into a container and place in the fridge to cool for 10-15 minutes.
Before making the drink, take the rims of the serving glasses and gently dip them on a plate of a sticky substance like agave nectar or honey.
Then, mix together salt, cumin, nutmeg, and pumpkin pie spice on a plate and dip the agave lined rim into the salt mixture.
Add a handful of ice cubes to a cocktail shaker.
Pour in the tequila, cointreau, pumpkin syrup, lime juice, pumpkin puree, and 3 dashes of angostura bitters.
Close the lid tightly and shake for 15-30 seconds.
Add about 5 medium sized ice cubes to the rimmed margarita glasses.
Remove the lid from the cocktail shaker and gently strain the drink into the glasses.
Garnish with any herbs and spices like cinnamon sticks, freshly grated nutmeg, or rosemary!