Preheat oven to 350 degrees (F). Line 2 baking sheets with parchment paper or silicone baking mat.
Add all the ingredients in a bowl and mix until completely combined.
Scoop cookie dough into tablespoon-sized portions and roll into a ball. Place on prepared baking sheets and lightly flatten the dough balls with either your hands or a spatula.
Bake, one pan at a time, for 9 - 11 minutes. The tops of the cookies should start to crack a bit but the centers should remain soft.
Cool cookies on the baking sheet for 5 minutes then remove to a wire cooling rack. Cool completely before frosting.
In the bowl of a standing mixer, whip the butter, vegetable shortening (if using) and a pinch of salt until creamy, about 2 minutes on medium speed.
Reduce the speed of the mixer to low and slowly add in approximately half of the confectioners' sugar and beat until incorporated.
Add the vanilla extract and 2 tablespoons half and half (or milk) and beat until smooth.
Beat in the remaining confectioners' sugar.
Increase the mixer speed to medium-high and beat for 2 minutes. If frosting is too stiff, slowly add additional half and half until desired consistency is reached.
Frost the completely cooled cookies and garnish with sprinkles. Allow the frosting to set before storing in an airtight container.
For seasonal-themed Sprinkled with Fun cookies, substitute 15.25 ounces white or yellow cake mix for the Funfetti mix. Gently stir in 1/3 - 1/2 cup seasonal-colored sprinkles to the batter AFTER all the cookie ingredients have been mixed together. Bake according to directions above.
*Feel free to use your favorite pre-made canned frosting.
Makes 30 - 32 cookies