• Preheat oven to 350℉. Line a baking sheet with parchment paper.
• In a large mixing bowl, cream together softened unsalted butter (½ cup, i.e. 1 stick), light brown sugar (¾ cup) and granulated sugar (¾ cup) for 1 minute.
• Mix in canned pumpkin puree (1 cup), sour cream (¼ cup), egg (1 large), and vanilla extract (1 teaspoon).
• Add baking soda (1 teaspoon), baking powder (1 teaspoon), pumpkin pie spice (2 ½ teaspoons), cinnamon (2 teaspoons), salt (½ teaspoon), and cornstarch (2 tablespoons). Mix until combined.
• Slowly add all-purpose flour (2 ½ cups) and mix until just incorporated. Do not overmix.
• Immediately after mixing, scoop dough into 4-tablespoon sized balls. Spray your hands with nonstick cooking spray and gently flatten each dough ball.
• Bake at 350℉ for 16-18 minutes. Because of how moist they are, these bake longer than the traditional cookie. While you do want to keep an eye on them to make sure they don’t over-brown, they do need to bake for the full time or else the tops will be gummy.

  (Of course, because ovens bake differently use your best judgement to keep them in longer if they look severely underbaked.)
• After removing from oven, allow the cookies to cool on the hot baking sheet for 15 minutes before removing them from cookie sheet. Allow cookies to fully cool before frosting.

To Make Frosting:

• Note: if you like a THICK layer of frosting, double the frosting recipe! If you're planning just to spread with a knife, use the recipe as-is.
• In a large bowl, beat the unsalted butter (¼ cup, i.e. ½ stick) and cream cheese (4-ounces) on medium speed using a hand or stand mixer (with paddle attachment) for about 1 minute (until light and creamy).
• Keeping the mixer on medium speed, slowly add in vanilla extract (1 teaspoon) and powdered sugar (1 ½ cups). Once incorporated, turn mixer to high speed and beat for 2 minutes until creamy.

  If your frosting is too thick, add 1-2 tablespoons of milk to thin it out. If it it too thin, add a bit more powdered sugar.
• Spread or pipe frosting on cooled cookies and top with a dusting of cinnamon or pumpkin pie spice, if desired. For the perfect cookie swirl, I use a large round tip.
• Store the frosted cookies in an airtight container in the refrigerator. These cookies stay soft & moist for 3-4 days.