It is an interesting cake. The hard part was to make the glaze which didn't work out as necessary. I'll try again some other time. Thanks!
¾ cup (180 gm) (4½ oz) (125 gm) good quality bittersweet chocolate, chopped
9 tablespoons (135 ml) (4½ oz) (125 gm) unsalted butter, softened at room temperature
1 cup (240 ml) (4½ oz) (125 gm) confectioners’ sugar (aka icing sugar or powdered sugar)
6 large eggs, separated, at room temperature (see note above about egg whites)
1 teaspoon (5 ml) vanilla extract
½ cup (120 ml) (7 oz) (100 gm) granulated sugar
1 cup (120 ml) (4½ oz) (125 gm) all-purpose (plain) flour (for volume measurement, spoon gently into measuring cup and level top)
pinch fine grain salt
Apricot Glaze (see recipe below)
Chocolate Glaze (see recipe below)
Writing Chocolate (see recipe below)
1 cup (240 ml) heavy whipping cream, cold
1. Preheat oven to moderately hot 375˚F/350°F fan/190˚C/gas mark 5 with a rack in the centre of the oven. Butter and flower the sides of a 9-inch (23 cm) springform pan, then line the bottom with a circle of parchment paper.
2. Place the bittersweet chocolate in a heat-proof bowl and heat over a small saucepan of barely simmering water (make sure that the bowl is not touching the simmering water) or in the microwave until just melted. Set aside to cool completely, stirring often.
3. Place the butter in a large mixing bowl and beat with the paddle attachment of a stand mixer or electric mixer on medium speed until very light and creamy. Add the confectioners’ sugar on low speed, then increase to medium speed and beat again until light and creamy.
4. Beat in the egg yolks, one at a time, scraping down the sides of the bowl.
5. Add the cooled chocolate and vanilla and beat until well-mixed and very light and creamy, scraping down the sides of the bowl.
6. In a scrupulously clean bowl using the whisk attachment, beat the egg whites with about one tablespoon of the granulated sugar on high speed until foamy. Gradually add in the rest of the granulated sugar and continue beating the whites until they form soft, shiny peaks - they should hold their shape but flop over on themselves.
10. Bake in the preheated moderately hot 375˚F/350°F fan/190˚C/gas mark 5 oven for 35-45 minutes (mine took exactly 40 minutes) or until a toothpick inserted in the middle comes out clean. The cake will crack and dome in the middle as it bakes but will flatten out as it cools.
13. Place 1 cake layer on the 8½-inch (22 cm) cardboard cake round and spread it generously with about half of the apricot glaze. Allow it to soak in.
14. Place the second cake layer on top and spread the top and sides with the remaining apricot glaze. Work quickly before the glaze has a chance to set and use a metal offset spatula to smooth the top. Place the cake on a rack set over a plate or baking sheet lined with waxed paper and allow the apricot glaze to set.
Apricot GlazeServings: 1 quantity (about 1 cup)
1¼ cup (300 ml) (14 oz) (400 gm) apricot jam or preserves (I used plum jam)
2 tablespoons (30 ml) rum (or other liquor) or water
1. Boil the jam and rum/water in a small saucepan over medium heat.
2. Cook, stirring often, until the mixture thickens and drips slowly from the spoon, about 2-3 minutes.
3. Strain through a wire mesh sieve, pressing firmly on the solids. You should have about 1 cup of glaze. Use warm.
Chocolate GlazeServings: 1 quantity
1 cup (240 ml) (7 oz) (200 g) granulated sugar
½ cup (120 ml) water
(4 oz) (115 gm) good quality bittersweet chocolate, chopped
1. Place the sugar and water in a small, heavy-bottomed saucepan over medium-high heat and bring to a boil, stirring occasionally.
2. Attach a candy thermometer and cook, stirring, until the mixture reaches 234˚F/112°C, about 5 minutes. If you don’t have a candy thermometer, use the method explained in this video.
3. Remove the saucepan from the heat and whisk in the chocolate. It might thicken up quite a bit. If it does, return it to low heat and add a few drops of water if necessary to thin it out to a runny, pourable consistency. The glaze should be smooth and shiny.
4. Off the heat, stir the glaze for 30-60 seconds to cool it slightly, then immediately use it to glaze the cake.
5. Any excess glaze can be stored in a container in the fridge and added to a mug of hot milk to make hot chocolate.
Writing ChocolateServings: 1 quantity
¼ cup (60 ml) (1.8 oz) (50 gm) chopped good quality chocolate
½ - 1 teaspoons vegetable oil
1. Heat the chocolate until just melted, then stir in enough vegetable oil to get a pipeable consistency. If necessary, let the chocolate mixture cool slightly to thicken so that it is not too runny.
2. Place the chocolate in a disposable piping bag or small Ziplock bag and snip off the tip to make a small hole. I recommend a practice run on waxed paper before writing on the cake.