Cake pan 25 cm x 30 cm

Method:

Line a half-sheet pan with parchment paper. Butter and flour the parchment and all sides of the pan; set aside. Preheat an oven to 175 ⁰C. Combine the pistachio powder and sugar¹ in a large mixing bowl. Add the milk and whisk firmly until ingredients are evenly moistened. Whisk in the flour; set aside.

In the bowl of an electric mixer fitted with the whisk, add the egg whites and whip them to a soft peak. As the egg whites begin to stiffen, add the sugar² and continue beating until fully combined. In small additions gently fold the meringue into the pistachio mixture until evenly distributed.

Carefully spread the biscuit batter onto the prepared pan in a rectangular shape roughly 25 cm x 30 cm. Using a offset palette knife smooth the surface and distribute the biscuit batter evenly. Sprinkle powdered sugar all over the top and bake for approx.15 minutes, or until the biscuit is baked throughout. Set the pan aside to cool.

Filling: place the butter into a medium size bowl. Add the powdered sugar and pistachio paste and combine the ingredients until the texture is smooth and creamy. Firmly whisk the egg yolks into the filling. Set aside.

Carefully trim the edges of the biscuit into a 25 cm x 30 cm rectangle and cut into three 10 cm pieces. Run a flat spatula or knife under the biscuit to separate it from the parchment. Cut both a piece of cardboard and parchment paper and lay them in that order on a rectangular serving platter large enough to comfortably accommodate the cake.

Transfer the filling into a large pastry bag fitted with a round nozzle. Place the first of the three biscuit pieces on top of the parchment. Pipe ⅓ of the filling in straight parallel lines lengthwise on top of the biscuit, carefully covering the entire surface. Place the second biscuit on top of the filling and repeat the same procedure. Top with remaining biscuit. Spread the remaining filling evenly on all sides of the cake. Coat all 4 sides of the cake with the ground pistachios and refrigerate. Top generously with powdered sugar before serving.