Recipe(tried): Double Crunch Chocolate Hazelnut Squares

i tried this recipe for a dinner gathering recently and it became a hit. now i got some orders for the up-comign festival season!
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Double Crunch Chocolate Hazelnut Squares

Crispy crunch layer:
4 ounces bittersweet chocolate, coarsely chopped
3 cups cornflakes

Deep chocolate-hazelnut crunch layer:
5 ounces bittersweet chocolate, coarsely chopped
3 ounces milk chocolate, coarsely chopped
1 cup heavy cream
2 tablespoons unsalted butter, slightly softened
1/2 cup blanched hazelnuts, toasted and chopped
1 teaspoon vanilla extract

White chocolate-hazelnut mousse layer:
1/4 cup water
2 teaspoons unflavored powdered gelatin
8 ounces white chocolate, chopped
1 3/4 cups heavy cream, divided
3 tablespoons hazelnut liqueur, such as Frangelico

Garnish:
Chocolate sauce
Toasted hazelnuts, chopped

Make the crispy crunch layer:

Line a 9-inch square baking pan with aluminum foil so that the foil extends 2 inches beyond 2 opposite sides of the pan. Lightly butter the bottom and sides of the foil-lined pan. Melt the chocolate according to the directions in Chocolate Melting Tips. Stir in the cornflakes. Scrape the mixture into the prepared pan and, using a small offset metal spatula, spread into an even layer. Refrigerate the crust while preparing the filling.
Make the deep chocolate-hazelnut crunch layer:

In the top of a double boiler over hot, not simmering, water, melt the chocolates with the heavy cream, stirring often, until smooth. Remove the pan from the heat. Whisk in the butter until melted and well combined. Whisk in the hazelnuts and vanilla. Transfer the mixture to a medium bowl. Put the bowl in a larger bowl filled with ice water. Stir the chocolate mixture until it is cool and begins to thicken. Scrape the mixture onto the crispy crunch layer and smooth into an even layer, making sure that the chopped nuts are evenly distributed over the crust. Cover the pan loosely with plastic wrap and refrigerate for 1 hour or until cold and firm.
Make the white chocolate hazelnut mousse layer:

Place the water in a small heatproof glass measuring cup. Sprinkle the gelatin over the water and let the mixture stand for 5 minutes to soften the gelatin. Place the cup with the softened gelatin in a small saucepan with enough water to come halfway up the side of the cup. Heat the gelatin mixture in hot, not simmering water. Stir the gelatin frequently for 3 to 5 minutes, or until the gelatin dissolves and the mixture is clear. Remove the pan from the heat, leaving the cup in the water to keep the gelatin mixture warm until ready to use. Place the white chocolate in a large bowl. In a small saucepan, bring 3/4 cup of the heavy cream to a gentle boil. Pour the hot cream over the chocolate and let the mixture stand for 1 minute to melt the chocolate. Whisk until smooth. Whisk in the warm gelatin and hazelnut liqueur. Place the bowl over a larger bowl of iced water and stir for 5 to 10 minutes, or until the mixture is cool. In a chilled medium bowl, using a hand-held electric mixer, beat the remaining 1 cup of cream at medium speed until it begins to form soft mounds. Do not overbeat or the mousse will be grainy. Fold one-third of the whipped cream into the white chocolate mixture. Fold in the remaining whipped cream. Scrape the white chocolate mousse over the top of the chocolate crunch layer. Refrigerate the dessert for 4 hours, until the mousse is set.
Cut and serve the squares:

Run a small paring knife around the edge of the pan where there is no foil to loosen the bars. Using the two foil ends as handles, carefully remove the bars from the pan. Gently peel off the foil. Cut the dessert into 9 squares, using a large, sharp knife and wiping the blade clean after each cut. Serve each square on a dessert plate, drizzled with chocolate sauce and sprinkle with chopped toasted hazelnuts.