For the hazelnut sponge cake:

1. Pre-heat oven to 375°F (190°C). Grease a 11 x 17 inch (28 x 43 centimetres) baking sheet, and line the bottom with greased parchment paper. Flour the pan and set aside.

2. In the bowl of a food processor, chop the hazelnuts into coarse crumbs, about 45 seconds. Add Redpath® Icing Sugar and flour and process until the mixture resembles fine crumbs, about 45 seconds.

3. In a large bowl beat the eggs and vanilla with an electric mixer until pale and thick, about 3 minutes; set aside.

4. Clean the beaters and, in a separate bowl, beat the egg whites and salt on medium speed until foamy. Slowly pour in the Redpath® Granulated Sugar and continue beating until the egg whites are firm and shiny. They should hold a stiff peak when the beaters are pulled away.

5. Sift the hazelnut mixture over the eggs in two additions, and gently fold in each addition using a rubber spatula. Fold the whites into the whole egg mixture in two additions. Pour the cooled melted butter down the side of the bowl; fold in.

6. Using an offset spatula, spread the sponge batter evenly onto the prepared pan. Bake until pale gold and dry to the touch, 10 minutes.

7. Remove cake and run a small paring knife around the edge to release it from the pan edges. Allow to cool for 10 minutes and then invert onto a fresh sheet of parchment paper. Peel off the parchment that lined the pan and allow to cool completely while preparing the other components of the Opera Cake.

For the coffee syrup:

1. Whisk together the water, Redpath® Granulated Sugar and coffee in a small pot. Bring to a boil for 1 minute and set aside to cool.

For the milk chocolate ganache filling:

1. Place the chocolate chips in a heat-proof bowl.

2. Heat the cream in a small saucepan until steaming and small bubbles start forming around the edge of the pan. Pour the cream over the chocolate and let sit for 1 minute.

3. Gently begin stirring the chocolate in the centre, slowly making bigger circles to incorporate the chocolate into the cream. Once smooth, chill for 1 hour.

For the sour cherry buttercream:

1. Combine Redpath® Granulated Sugar and water in a medium heavy bottomed saucepan. Place over medium heat and, with gently stirring, dissolve the sugar. Once the sugar is dissolved and begins bubbling, stop stirring. Cook while occasionally brushing down the sides of the pot with a clean, wet pastry brush, until mixture reaches 240℉ (116℃) on an instant read or candy thermometer, about 8 minutes.

2. While the sugar mixture is coming up to temperature, begin beating the egg yolks with an electric mixer on medium speed. Beat for 5 minutes until yolks are thick and pale yellow. Beat in vanilla and salt.

3. With the mixer on medium low, slowly begin pouring the sugar syrup into the yolk mixture, a few tablespoons at a time. Try to avoid pouring into the beaters directly so the syrup does not spray, but quickly beat in each syrup addition once it is in the yolks.

4. Once the syrup is incorporated, begin adding the butter a couple pieces at a time. Beat well between each addition. Once all the butter has been added, beat the buttercream for an extra 2 – 3 minutes. Fold in the sour cherry jam with a rubber spatula.

For the assembly:

1. Cut the hazelnut sponge into 3 rectangles 5 1/2 x 11 inches (14 x 28 centimetres).

2. Place the ⅓ cup (57 g) of chocolate chips in a small heatproof bowl and microwave on medium heat in 15 second increments, stirring mixture in between each increment until melted.

3. Brush the melted chocolate on one rectangle and allow to become firm, about 30 minutes.

4. Once chocolate is firm, flip the coated piece of cake so the chocolate is on the bottom. Brush cake generously with coffee syrup.

5. Using about 1¼ cup of buttercream, spread cake with a layer ⅜ inch (1 centimetre) thick. Top with a second rectangle of cake and brush with syrup.

6. Spread second cake layer with chilled ganache and ¼ cup (77 g) sour cherry jam; top with last rectangle of cake and brush with syrup.

7. Spread cake again with a ⅜ inch (1 cm) layer of buttercream. Chill cake until firm, about 3 hours in the refrigerator or 1 hour in the freezer.

8. When cake is chilled, make the milk chocolate glaze using the same method as the milk chocolate ganache filling, adding the vegetable oil at the very end.

9. Spoon the warm glaze over the chilled cake, smoothing the top with an offset spatula. Do not worry about covering the sides of the cake with glaze. Chill for 1 hour in the refrigerator.

10. Fill a container large enough to dunk a long, sharp knife with hot tap water. Immerse the knife, wipe off the water with a clean cloth and trim ¼ inch (5 millimetres) off one side of the cake; repeat with remaining sides.

11. To serve, use a warm, clean knife to slice pieces about ¾ inch (1.5 centimetres) thick. Opera Cake will keep for up to 4 days in an airtight container in the refrigerator. Allow to sit at room temperature for 20 minutes before serving.