Pre-heat oven to 180C / 350F.
Butter the sides of your springform pan and line the base with parchment paper. Set aside.
Remove seeds from cardamom pods. Discard pods. Crush seeds in a pestle and mortar till it looks like dust. If you don’t have a pestle and mortar, wrap the seeds in a newspaper and crush with a rolling pin (or the base of your frying pan). Set aside.
Melt the dark chocolate, butter and sugar together in a saucepan over very low heat. This should take about 7-10 minutes. You may be tempted to turn the heat up, but this will only scorch your chocolate. Patience is key here (you can melt the mixture in a double boiler, too, if you like, but I wanted to use as few cooking vessels/utensils as possible - with an eighteen-month-old, even one extra pot is one too many). Stir occasionally, until the chocolate mixture is smooth. Be patient and vigilant. Turn off the heat, set the saucepan aside and allow to cool completely.
Once the chocolate mixture has cooled, transfer to a mixing bowl and add cardamom dust and ground clove powder. Whisk in the eggs, one by one. If you are using a stand or hand mixer, set the speed to medium. You will note that as you add more eggs, the egg and chocolate mixture will fluff up and resemble chocolate mousse.
Turn the mixer off and add salt and fold in flour by hand. Do not over mix.
Transfer into the springform pan and place in the middle of your oven for 40-45 minutes (ovens vary, so keep a vigilant eye on the cake after the 40-minute mark). When ready, your skewer/toothpick inserted in the middle will be very slightly damp, with a bit of the cake batter on it; that is fine. You don't want the cake to overcook and have a dry texture.
Remove from oven, and allow to cool in the springform at room temperature. Adorn with edible rose petals (if using) and crushed pistachios (if using). If you are not using either of the two, you can also simply dust the cake with some caster sugar.
Enjoy with crème fraîche on the side.