1 cup flour

½ cup unsweetened cocoa

¼ teaspoon salt

½ cup unsalted butter, softened

3 eggs

1 ½ cups heavy whipping cream

1 ¼ cups plus 1 tablespoon sugar

20 crème de menthe thin mints

Preheat the oven to 350°.  Grease 15 ½ x 10 1/2 -inch jelly-roll pan; line with waxed paper.  On another sheet of waxed paper, combine flour cocoa and salt.  In a large bowl, with a mixer on low speed, beat butter and 1 ¼ cups sugar just until blended.  Increase speed to high; beat 3 minutes or until mixture is light and creamy, frequently scraping bowl with rubber spatula.  Reduce speed to low; add eggs, one at a time, beating well after each addition.  Add flour mixture; beat just until combined, occasionally  scraping bowl.  Pour batter into the prepared pan and spread evenly.  Bake for 15 to 18 minutes or until a toothpick inserted in the center comes out clean.  Cool cake completely in a pan on a wire rack, about 40 minutes.  Meanwhile, with vegetable peeler, shave a long side of each mint lengthwise to equal ½ cup chocolate curls.  Set aside curls for sprinkling on top of assembled cake.  Chop broken pieces and reserve for use in filling.  With a small knife, loosen cake sides from waxed paper; invert cake onto cutting board.  Carefully remove waxed paper.  With a sharp knife, trim ¼ inch from each side of the cake.  Cut the cake crosswise into 3 equal rectangles (about 9 ½ x 4 ½ -in. each).  In a medium bowl, with a mixer on medium speed, beat cream and remaining 1 tablespoon sugar until stiff peaks form.  With rubber spatula, gently fold reserved chopped mints into whipped cream.  Place 1 cake rectangle on a serving plate; top with 1 generous cup whipped cream mixture and spread evenly.  Repeat 2 times with remaining cake and cream mixture.  Sprinkle top with mint-chocolate curls.  Cover and refrigerate.