Turrón de Chocolate (Chocolate Biscuit Cake)

Grease 9-inch springform pan with 1 tablespoon butter.

With whisk attachment, mix remaining 3 sticks butter and confectioners’ sugar in large bowl on low speed until incorporated, about 30 seconds. Increase speed to medium-high and whip until light and fluffy, about 2 minutes.

Reduce speed to low, add cocoa powder, and mix until incorporated, about 30 seconds. Increase speed to medium-high and whip until cocoa is fully incorporated and mixture is light and fluffy, about 2 minutes, scraping down sides and bottom of bowl with rubber spatula as needed.

Add egg yolks, one at a time, whipping well after each addition.

Add vanilla and salt and whip just to combine.

Add cookie pieces and, with rubber spatula, gently fold in until cookie pieces are covered in chocolate mixture.

Scrape mixture into prepared pan, pressing down gently. Cover turrón with plastic wrap and freeze at least 4 hours

When turrón is frozen and ready to serve, stir sugar and water in heavy-bottomed medium saucepan over medium-low heat until sugar dissolves. Increase heat to medium-high and boil syrup until it registers 240°F on candy thermometer, 5 to 7 minutes.

While syrup is boiling, with whisk attachment, beat whites and salt on medium speed until loosened, about 1 minute. Increase speed to medium-high and whisk until soft peaks form, 2 to 3 minutes.

With mixer running on medium-high speed, slowly and carefully add syrup to egg whites. Beat until outside of bowl is cool to the touch and whites are thick and glossy, about 7 minutes.

Release frozen turrón from pan and place on serving platter.

Spread meringue decoratively on top and sides. Allow to sit at room temperature about 10 minutes before cutting with a serrated knife.