Preheat oven to 375. In a large bowl, combine flour, baking powder, baking soda, cinnamon, and salt.
In a stand mixer, combine Crisco, butter, and sugar. Mix until smooth about 3 minutes. Add egg, canned pumpkin, and vanilla and combine until smooth.
Slowly add the flour mixture 1/3 at a time to the wet ingredients, mixing after each addition. Scrape down the sides of the mixing bowl with a spatula and mix to make sure the batter is all combined.
With a medium cookie scoop, scoop dough onto cookie sheets. Be sure to leave 2 inches between each cookie dough ball. Bake for about 10 minutes until fluffy, cooked through, and light golden brown. Let cool.
For the frosting, add butter and brown sugar into a small saucepan over medium low heat and slowly stir until melted. Add milk and vanilla. Turn heat to low and add powdered sugar and stir until combined. Let cool off heat.
Frost cooled cookies with frosting and serve. Keep extra cookies in the refrigerator for 3-4 days in an airtight container.
Notes
Katie's Tips:*To go all out, just use all Crisco. It will make the cookies even lighter and fluffier. I won't tell anyone.*The original recipe uses 1 cup powdered sugar, but I found it was more of a glaze. I like to add more powdered sugar, so the consistency is frosting like. *I lay parchment paper down over my cookie sheets for easy clean up after baking.*Watch the baking time closely. Some ovens will take 11-12 minutes to bake these perfectly. *For busy days, bake cookies ahead of time. Store in an airtight container on the counter. Make frosting later and frost right before serving.*Libby's Pumpkin looks like this! I always buy 2 or 3 cans, so I have some on hand for fall baking. *A medium cookie scoop is 2 3/4 inches in diameter like this one. *I find making frosting to be a little bit of an art and a science. The recipe above works; but if it thickens too much just add a little milk to it over low heat and stir until is loosens up. If you want it thicker, you can add more powdered sugar. For crazy frosting lovers, consider doubling the recipe to have extra for frosting. If it looks clumpy from powdered sugar bits, put over low heat and whisk vigorously. *Room temperature baking ingredients are always best for even and smooth batter.*Unsalted butter is preferred, so you can control how much salt is in your recipe.*The light brown sugar should be lightly packed when measuring.*Baking powder and baking soda both have a shelf lives. Opened containers should be used within 6 months.