Preheat the oven to 350 degrees F and line 12 cupcake tins with paper liners.

In a large mixing bowl, combine the flour, brown sugar, baking powder, instant espresso, and pumpkin pie spice. 

In another bowl, combine the vegetable oil, pumpkin puree, whole milk, ¼ cup coffee, eggs, and vanilla. 

Add the wet ingredients to the dry and mix just until they are combined, be sure not to overmix! 

Divide the batter between the tins, filling each one ¾ of the way full. 

Bake the cupcakes for 14-16 minutes, or until a toothpick inserted into the center comes out clean. 

While the cupcakes are warm, remove them to a wire rack and poke the top a few times with a fork.

Drizzle over the remaining ¼ cup of coffee. I added about 1 teaspoon to the top of each cupcake. 

Set the cupcakes aside to cool completely before frosting. 

Add the butter to the bowl of a stand mixer fitted with the paddle attachment and beat it on medium speed until smooth. 

Add in the vanilla, espresso powder, and pumpkin pie spice. Mix to combine. 

With the mixer on low speed, add the powdered sugar a little at a time. 

Once all of the sugar has been incorporated, turn the mixer to high speed and beat until the frosting becomes light and fluffy. 

Transfer the frosting to a piping bag fitted with your choice of tip - I used a Wilton 2A. 

Pipe the frosting on the cooled cupcakes and garnish with a sprinkle of cinnamon. 

Enjoy immediately or store in an airtight container in the fridge for up to two days.