Preheat oven to 350F and line a cupcake tin with cupcake liners.
In a large bowl, sift together the flour, baking powder, and baking soda. Add the sugars, pumpkin pie spice, cinnamon and salt and mix to blend together.
In the bowl of a stand mixer or with a hand mixer, blend together the pumpkin puree, egg, vegetable oil, Greek yogurt, milk and vanilla extract until smooth.
Add the dry ingredients to the wet ingredients. Mix until combined.
Divide batter into the prepared cupcake liners and bake for 24-27 minutes or until a toothpick inserted into the center comes out clean. Let cool completely before frosting.
Once the cupcakes are completely cooled, make the frosting by adding the cream cheese, butter, and icing sugar to a food processor with the paddle attachment. Blend on medium speed until it is light and fluffy. If frosting is too thick, add a little milk 1 tablespoon at a time until you reach your desired consistency. [Note: the frosting recipe produces enough frosting for 18 cupcakes, depending on how heavily you frost your cupcakes].
Frost cupcakes. [Optional: Drizzle some caramel topping on top of the frosting.]