Preheat oven to 350 F and line baking sheets with parchment paper.
Whisk together the flour, baking soda, and salt Set aside.
Cream the sugar and butter in the bowl of an electric mixer with the paddle attachment or with a handheld mixer on medium speed until just combined.
Scrape down the sides of the bowl then add the egg and blend well then add the vanilla.
With the mixer on low speed, alternatively add the dry ingredients with the sour cream.
Stir in the chocolate chips.
Use a 2 tablespoon cookie scoop to drop the cookies onto the cookie sheet. Place them 2" apart.
Bake 10-12 minutes. Let cool on the baking sheet for 10 minutes before then transferring them to a rack to cool completely.
ASSEMBLING THE COOKIE SANDWICHES
Place a large scoop of ice cream (about 1/4 cup) on the bottom of a cookie. Gently press another cookie on top. Coat the sides with sprinkles or chocolate chips.
Enjoy immediately or wrap tightly with plastic wrap and place in a freezer bag in the freezer to enjoy later.
Notes
*The cookie recipe calls for 1/2 an egg. For 1/2 an egg, simply crack and whisk and egg and carefully drop in about 1/2 of it into the recipe. It doesn't have to be exact!