This recipe involves two steps -- mixing the cookie dough and filling the baked cookies with ice cream. The results are worth the effort: The finished product looks like store-bought ice cream sandwiches but tastes even better!
In a medium-sized bowl, cream the margarine and brown sugar (using margarine instead of butter and brown sugar instead of granulated sugar produces a chewy, soft cookie). Beat in the eggs, one at a time, then the vanilla extract.
In a separate bowl, stir the cocoa, flour, baking powder, and salt. Gradually add to the margarine mixture. Beat until well combined. Gather the dough into a ball and chill for at least 1 hour.
Heat the oven to 375 degrees. On a lightly floured surface, roll out the dough to 1/4-inch thick. Use a ruler and a sharp knife to cut out rectangular pieces. (We made large cookies, about 2 1/4 by 5 inches, but you can make them smaller.)
Transfer the cookie rectangles with a spatula to an ungreased baking pan. Ask your child to use the tines of a fork to make patterns on the cookies.
Bake the cookies for 8 to 10 minutes or until set. Cool on a cooling rack.
Meanwhile, cut rectangular blocks from the ice cream. To do this, peel back the half-gallon carton from the ice cream, and cut 1/2-inch-thick slabs that are roughly the dimensions of your baked cookies. Return the blocks to the freezer.
Once the cookies have thoroughly cooled, place one ice cream block between two cookies. Trim the sides with a knife, wrap the sandwich in foil, and freeze for several hours. Repeat until you have used all the cookies and ice cream. Makes enough dough for 6 large sandwiches.