Line a 10" (25cm) cake pan with parchment paper, with a collar that extends at least 1-2 inches (2-4cm) above the height of the tin.* Preheat the oven to 325 degrees F (160 degrees C).

*You can just line the base of the pan, without a collar, if you are using a cake with sides that are at least 3 inches (6cm) tall.

In a large mixing bowl or the bowl of an electric mixer, whisk together the eggs and sugar. Beat on high speed until the mixture is a very light, pale yellow colour and about 3x-5x it's original volume (about 5 minutes).

Sift together the flour and cocoa in a separate bowl; set aside.

When the egg and sugar mixture is done, add the oil and milk (without stirring), and then fold in the flour and cocoa until just combined and all of the ingredients are well incorporated (the mixture should resemble a fluffy chocolate mousse).

Note: Over-mixing the batter will reduce the volume/fluffiness of the cake, and under mixing will prevent all of the ingredients from binding together properly. For best results, use a large spatula to fold the ingredients together until well incorporated.

Scrape the batter into your prepared tin and smooth the top. Bake for 45 minutes or until a toothpick inserted into the centre comes out clean.

Allow the cake to rest in the pan for 10 minutes, and then turn it out onto a wire rack to cool completely. Or, if baked in a springform pan, remove the collar and allow the cake to cool upright.

Pour the cherry juice into a medium heavy bottomed saucepan, and bring it to a boil.

Whisk in the sugar until dissolved, add the cinnamon, and then slowly pour in the cornstarch/water mixture.

Cook until thick and bubbly, and stir in the whole sour cherries. Continue to cook the cherries a minute more, or until the mixture is well combined and bubbly.

In a large mixing bowl or the bowl of the electric mixer, combine the whipping cream and sugar (if desired).

Meanwhile, in a heat-proof mug, sprinkle the gelatine over 1/4 cup of cold water until softened. Place the cup into a small pan of simmering water, and stir occasionally until the gelatine has dissolved, and there are no more visible grains on your stirring spoon.

Beat the cream until it just begins to thicken, and slowly pour in the warm gelatine mixture (do not scrape out the cup; use only what pours into the cream easily).

Beat the cream until stiff peaks form. Set aside.

Using a vegetable peeler, shave the chocolate bar into small shavings and curls. Separate the best looking curls for the top. Set the chocolate aside (in the refrigerator is ideal).

Wash the cherries if you plan to use them. Set aside.

Using a long, serrated knife, divide the cake into 3 equal sized layers. Place one layer on a large serving plate, and wrap a collar of clear acetate around the outside, securing it into place with scotch tape. (Alternatively, you can assemble the cake inside the collar of a 10" (25cm) springform pan, provided that the cake hasn't shrunk too much.)

Pour the warm (or hot) cherry mixture over the bottom layer of cake, spreading the cherries evenly right to the edge, against the collar. Place a second layer of cake on top, and set the cake in the fridge to cool for at least 1 hour (or until the cherries are no longer warm).

Once the cherries are cool, whip the cream according to directions above. Scrape about 1/2 of the whipped cream onto the cake. Spread the cream evenly over the middle layer of cake, and top with the final layer of cake. Carefully run a knife around the inside of the collar or pan, and gently remove it.

Spread a thin layer of cream on the top of the cake and around the edges (thick enough on the top to look white, thin enough on the sides just to make it sticky for the chocolate shavings).

Score the top of the cake into 16 wedge slices with the back of a sharp knife.

Using your hand, gently press the chocolate shavings against the sides of the cake so that they stick to the cream. Once you are done, brush the excess off of the plate/work surface into a container to use for the top.

Pour the reserved chocolate shavings into the centre of the top of the cake, putting the best looking curls in the middle. The chocolate should cover about a 4-inch (10cm) diameter in the centre.

Scrape the remaining cream into a piping bag fitted with a large star tip (I used tip #864). Pipe little rosettes onto the edge of each marked slice, and top with a fresh cherry (if desired).

Refrigerate until serving (a minimum of 2 hours is ideal to make the cake easier to slice).