To make the filling: In medium size bowl combine all ingredients except the mini chips. Mix until combined. (I use a hand mixer). Add the chocolate chips and fold to evenly incorporate. Cover with plastic wrap and put in the fridge while you prepare and bake the cookies.
To make the cookies: Pre heat oven to 350 degrees. Line baking sheets with parchment paper and set aside.
In medium size bowl, combine flour, baking soda, baking powder and salt. Stir with a spoon or fork to combine. Set aside.
In large bowl, with hand mixer, combine butter and sugar and mix until smooth and airy (about 2-3 minutes). Add eggs and vanilla and continue to mix remembering to scrape down the sides of the bowl. When mixture is smooth, add half the dry ingredients into the wet and mix on low. Add the rest of the dry ingredients until dough is smooth. Don't be surprised if the dough is sticky. It's supposed to be.
Using a teaspoon or small cookie scoop, form dough into small balls about 3/4 inch each. Place on baking sheets, flatten slightly with a spoon and bake 10 minutes. Remove from oven and cool slightly on cooling rack, then remove to paper or kitchen towels to cool completely. You will get about 90 cookies.
Remove filling from the refrigerator and when cookies are cooled, take a teaspoon of the filling and place it on the flat side of a cookie. Now take a second cookie and cover the filling to make a sandwich. Now you only have 44 more times to do this. But it's worth it. Dust with confectioners' sugar.
If ninety cookies seems daunting, make the cookie balls bigger, 1-1/4 inches in diameter and bake them 12 minutes. I've done this too. The work does go faster and the end result is just as delicious.
I store these in the refrigerator wrapped in an air tight container, and take them out about 20-30 minutes before I serve them.