1cupunbleached all-purpose flouror weigh out exactly 5 oz/140 grams**
½cupDutch process cocoa powder (measure carefully)natural okay, too**
¼teaspoonsalt
⅛teaspoonbaking soda
⅓cupmini chocolate chips (optional)
2largeeggs
⅔cupgranulated sugar(130 grams)
¼cupchocolate syrup
½teaspoonvanilla extract
8tablespoonsunsalted butter, melted and cooled(114 grams)
2pintsof your favorite ice cream.
Instructions
Preheat oven to 350 degrees F.
Line an 11x17 inch jelly-roll pan or something close to with parchment. If making half batch, you can use a 9-inch square pan.
In a medium size bowl, thoroughly mix together the flour, cocoa powder, salt and baking soda. If you want, you can throw in some mini chocolate chips (optional).
In a large mixing bowl using a handheld electric mixer, beat the eggs and sugar for about a minute. Beat in the chocolate syrup, vanilla extract and butter until mixture turns light brown. With a heavy rubber scraper or a spoon, stir in the flour mixture until incorporated.
Pour batter into lined pan. It is actually very thick, so you'll also have to scrape. Spread it as evenly as you can. It will be a thin layer. Also, try to make the top as even as you can because the brownie doesn't change shape much as it bakes. One way I do this is by dampening my fingers with a little water and tap, tap, tapping the top without getting too much water onto the batter itself.
Bake 10-12 minutes (maybe even up to 15) or until cakes seem firm and set. Remove from oven and let cool completely. Lift from pan and set cookie on a large cutting board.
Cut the cookie lengthwise to make two long rectangles, then cut cross-wise to make 4 rectangles (this makes them easier to work with). Place one of the rectangles on a big sheet of plastic wrap and spoon ice cream evenly over the top. Cover with second rectangle and press down slightly. Wrap tightly in plastic. Repeat with second set of rectangles. Set on a baking sheet and put in the freezer overnight or until very firm.
Using a large knife, trim the sides to give the sandwiches a clean edge. Cut each section into 4 rectangles.
Notes
Cook's Illustrated used a 5 oz/140 gram cup. I think a 4.5 oz/130 gram cup is better.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.