1 cup (2 sticks) unsalted butter
2 cups water
1 cup canola oil
4 cups sugar
1 cup high-quality unsweetened cocoa powder
4 cups all purpose flour
4 large eggs
1 cup buttermilk
1 tablespoon baking soda
1/2 teaspoon salt
1 tablespoon vanilla extract
Whipped Cream Frosting
4 cups chilled heavy whipping cream
1 1/4 cups powdered sugar
4 ounces high-quality bittersweet chocolate, chopped into small pieces
1/2 cup heavy whipping cream
1/4 cup Lyle’s Golden Syrup (I used light corn syrup)
2 teaspoons vanilla
To make the cake: For a 3-layer cake, place one baking rack one -third from the bottom of the oven and the second two-thirds from the bottom. Preheat the oven to 350°F. Line the bottom of three 9-inch or two 10- inch cake pans with parchment paper rounds, grease with butter, and dust with flour (or spray with Baker’s Joy).
Combine the butter, water, and canola oil in a medium saucepan set over medium heat.
In a large bowl, stir together the sugar, cocoa, and flour.
Pour the butter mixture into the sugar mixture and whisk until smooth. Whisk in the eggs, one at a time.
Then whisk in the buttermilk. Whisk in the baking soda, salt, and vanilla all at once. Transfer the batter to the prepared pans.
For a 3-layer cake, stagger the cake layers on the oven racks so that no layer is directly over another. Set two layers on one rack and the third on the other.
For a 2-layer cake, stagger the layers on the middle rack with one placed more toward the front of the oven and one toward the back.
Bake for 35 to 40 minutes, or until a toothpick inserted in the middle of each layer comes out clean. Monitor the layers carefully for doneness; each one maybe done at a different time.
Remove the cakes from the oven and cool on racks for about 15 minutes before inverting onto baking racks. Cool the cakes completely, at least 2 hours, before frosting.
To make the frosting: Using a mixer fitted with a whisk attachment, whip the cream in a large bowl on high speed until soft peaks form. Add the powdered sugar and whip until thoroughly combined.
Place 1 cake layer on a platter and spread some of the frosting over the top.
Top with the remaining layer or layers, thickly coating the top and sides of each with frosting.
Refrigerate the cake until the whipped cream frosting has stabilized, at least 1 hour.
To make the glaze: Place the chocolate in a medium bowl. Heat the cream in a small saucepan over medium heat until it is very hot and just beginning to steam. Pour the hot cream over the chocolate and stir until it has melted completely.
Stir in the syrup and vanilla.
Pour the glaze into a medium pitcher or measuring cup and let cool for 10 minutes. Do not let the glaze sit longer because it will stiffen and become difficult to pour over the cake. Slowly pour the glaze over the cake, ensuring that it covers the top and drizzles down the sides.
Cover the top of the cake entirely, but make sure some of the cream frosting shows through the drizzles on the sides.
If the glaze doesn’t flow easily over the edge of the cake don’t be afraid to add an extra tablespoon or two of Lyle’s Golden Syrup.
Refrigerate the cake until the glaze is set and the whipped cream frosting is firm, at least 1 hour. Slice the cake with a long serrated knife, dipping it in a tall glass of hot water between each slice. The refrigerated cake will keep for about 2 days.