Cream together the sugar, shortening, eggs, salt and vanilla.
In a microwave safe bowl, melt the chocolate chips in the microwave according to the package directions.
Add the chocolate to the sugar mixture and mix well.
Add the baking soda into the sour cream and mix until combined. Add the sour cream alternately with the flour into the sugar mixture. You'll need 4-5 cups of flour, keeping the dough soft and adding just enough flour so that the dough can be easily handled.
Mix in the chocolate chips.
Chill the dough for 3 hours.
Once the dough has been chilled, roll it out to 1/4" thickness. Use cookie cutters to cut shapes.
On a non-stick baking sheet, bake the cookies in a 350 degree oven for 8 minutes. Our cookies were about 3" in diameter. If your cut-outs are larger, they may take another minute or two to bake.
Once the cookies are cool, frost them as desired. We melted 8 ounces of chocolate chips and used a teaspoon to spoon chocolate into the center of the flour. Immediately sprinkle the chocolate with colored sprinkles before the chocolate sets.
Notes
Our cookies were about 3" in diameter and we got about 6 dozen cookies. If your cookie cutters are larger or smaller, you will yield a slightly different amount of cookies.