1. Place racks in upper-middle and lower-middle of oven and heat to 350 degrees. Combine butter and sugar in the bowl of a stand mixer fitted with a paddle attachment and mix on medium speed until smooth, about 1 minute.
2. Scrape down bowl, add eggs and vanilla, and mix until just combined. Add flour, nuts (if using), cocoa powder, baking soda, baking powder, and salt and mix on low until everything is well incorporated.
3. Divide dough into 30 portions (about 2 tablespoons each), roll into balls, and place 2" apart on 2 baking sheets. Using the bottom of a drinking glass, flatten to about a 2" diameter. Bake until edges are just firm, 12 to 14 minutes. Let cool 5 minutes before transferring to a wire rack; let cool completely before making sandwiches. Allow baking sheets to cool before repeating with remaining dough.
4. To assemble, sandwich about 2 tablespoons ice cream between 2 cooled cookies and lightly press down to spread ice cream to the edges. Place sandwiches on a plate, cover with plastic wrap, and freeze until firm, about 30 minutes.
Source: Hannaford fresh Magazine, September - November 2016