How to Make It
Beat heavy cream in bowl of a stand mixer fitted with whisk attachment on medium-high speed for 2 minutes. Add powdered sugar, and beat until stiff peaks form. Reserve 3/4 cup whipped cream for topping. Stir chopped mint into remaining whipped cream.
Line an 8 1/2 x 4 1/2 loaf pan with plastic wrap. Remove tops of the 7 Oreo Cookies, and discard tops; shingle cookies, green filling side down, along center of prepared pan. Add half of the mint whipped cream to pan, and spread in an even layer. Roughly chop 12 of the Oreo Thins, and sprinkle evenly over whipped cream. Add remaining mint whipped cream. Cut remaining 6 Oreo Thins in half; arrange, cut side up, along edge of pan and even with rim. Fold plastic wrap over cake, and freeze at least 8 hours.
Invert cake onto a serving plate; discard plastic wrap. Drizzle with chocolate syrup, and top with reserved whipped cream. Garnish with fresh mint, and more cookies if desired.