1quartof your favorite ice cream, or mix and match
⅔cupunbleached all-purpose flour(90 grams)
⅓cupunsweetened cocoa powder(28 grams)
¼teaspoonsalt
⅛teaspoonbaking soda
1largeegg
1largeegg yolk
½cupgranulated sugar(100 grams)
3tablespoonschocolate syrup(60 grams)
1teaspoonvanilla extract
4tablespoonsunsalted butter, melted and cooled(56 grams)
2tablespoonsneutral vegetable oil
Instructions
Line an 8-inch square pan with plastic wrap, leaving enough overhang to lift out the ice cream later. Spread slightly softened ice cream evenly in the pan. Cover tightly with plastic wrap and freeze until completely firm.
Preheat oven to 350 degrees F.
Spray a 9x13inch pan or two 8-inch pans with cooking spray and line with parchment paper.
In a medium size bowl, thoroughly mix together the flour, cocoa powder, salt and baking soda.
In a large mixing bowl using an electric mixer, beat the egg, yolk and sugar for about a minute. Beat in the chocolate syrup and vanilla extract and beat for another 2 minutes. Add butter and oil and beat until mixed, then with a heavy rubber scraper or a spoon, stir in the flour mixture until incorporated.
Pour batter into lined pan. Using a rubber scraper, scrape it as evenly possible across the surface of the pan. For extra smoothness, you can dampen your fingers ever so lightly with water and tap, tap, tap across the top.
Bake 10-12 minutes or until until it seems firm and set. Remove from oven and let cool completely. Lift from pan and set cookie on a large cutting board.
Cut the cooled cookie into two equal rectangles. Place one rectangle, cut side up, on a large sheet of plastic wrap. Lift the frozen ice cream from the pan, peel away the plastic, and center the ice cream square on top of the cookie. Place the second cookie rectangle on top, cut side down, gently pressing just until the layers adhere.
Wrap the entire sandwich tightly in plastic wrap and freeze until very firm, at least 2 hours. Cut into bars or squares with a large sharp knife, wiping the blade clean between cuts if needed.
Notes
Cook's Illustrated used a 5 oz/140 gram cup. I think a 4.5 oz/130 gram cup is better. Also, ¼ teaspoon of salt is on the low end. You may want to add a pinch to bring out the flavor.Natural cocoa powder like regular Hershey's or Ghirardelli will give you a slightly fluffier cake. Also, measure it carefully or weigh it because too much cocoa will dry them out.