Heat oven to 350 degrees F.
On clean work surface, knead 1/2 cup chopped sugared walnuts into cookie dough. Shape dough into 1-1/2-inch balls, using about 1 level tablespoon for each. Place 2 inches apart on ungreased baking sheets. (Youll need 24 cookies for sandwiches; save extras for snacking.)
Bake in 350 degree F oven until golden around edges (centers will be soft), 12 to 14 minutes. Let cookies cool on sheet on wire rack 1 minute. Remove cookies to rack to cool completely.
Place remaining walnuts in bowl. With sharp knife, cut crosswise through ice cream and container to remove strawberry ice cream along the edge of flavor (see photo 1). Freeze remaining ice cream. Cut strawberry ice cream lengthwise into two 1/2-inch wide slices. Using a 2-1/2-inch biscuit cutter, cut out 2 circles from each slice, for a total of 4. Place each circle on flat side of cookie; top with another cookie, flat side down. Roll edge in remaining chopped walnuts.
Place ice-cream sandwiches on a foil-lined baking sheet; freeze. Repeat with chocolate and vanilla ice cream, working with one flavor at a time, and making 4 sandwiches of each flavor. Freeze at least 1 hour. If freezing longer, cover with plastic wrap. (Save remaining ice cream for snacking.)
Sugar-coated walnuts available from Diamond, 800-344-9889 or www.diamondnuts.com. Makes 12 sandwiches.