Wash your mandarins, and wash them especially well if they're store bought as the skins are part of this recipe. Then put six of them (skins and all) into a saucepan with plenty of cold water, cover and bring to a simmer. Let them gently cook for about an hour until they're nice and soft. Drain and cool until you can handle them, then remove the stems. When I picked my mandarins, if I yanked them off the tree it left a big hole in the skin where the stem should be. You don't want this. I imagine they'd disintegrate during cooking. Make sure the skins are intact, with no holes. If you're picking your own the trick to hole-free skins is twisting them off the tree instead.
Preheat your oven to 180C fanbake.
Put the mandarins into your food processor and whizz until fairly smooth. They smell good huh?
Roughly grind the cardamom seeds in a mortar and pestle. I put the whole pods in, gave them a bash to split the skins then separated out the seeds. This also smells off the charts good. Just saying. You could use ground cardamom if you can't find whole pods, but neither the smell or the taste will be the same.
Add all ingredients (except for your remaining three mandarins) to the cooked mandarins in the food processor and whizz until smoothish. Some chunks of date is fine, and delicious.
Pour cake batter into a greased and lined tin. I used a shallow rectangular slice pan as this cake doesn't rise much.
Bake for about 45 minutes, until a skewer comes out clean. Cover your cake with tinfoil after about 25 minutes to prevent it browning too much.
Remove from the oven, poke holes all over the cake with a skewer, and spoon the juice of your remaining three mandarins over the cake while still hot. Take your time with this, you want the juice to soak in evenly and the whole cake to get some love. Leave to cool in the tin.
Serve warm with a glass of sweet peppermint tea, and dream yourself some place else.