I use a baking spray for my mould and it is excellent. I have a Nordic ware very ornate mould (love it) and I was worried the fine detail would be lost when I unmoulded, iyswim. To use the baking spray I recommend spraying each little crack and crevice and then going over the whole lot with a pastry brush (or any kind of small clean brush) to make sure the cake comes out really cleanly. I bought my baking spray from amazon but I think if you google you can get homemade recipes for it as well (I think it's basically oil and flour).
Hope it works. Ovens differ but you will know if your cake is done if a skewer comes out clean when you've inserted it. Do you have a fan assisted oven? If so you will probably need 5-10 minutes less time. Also do not open the oven at all while baking. Hth!
PREHEAT OVEN TO 175C 1. Sift flour and cocoa 2. Cream sugar and butter until pale and fluffy 3. Add eggs into creamed sugar/butter mixture one at a time, fully incorporating each egg 4. Add in dry ingredients, baking soda, and yoghurt in thirds. Mix gently (will help have a lighter cake) 5. Mix in vanilla 6. Put mixture into prepared pan 7. Bake for 45-55 minutes 8. Cool for 10 minutes before inverting onto a rack to cool completely
Tip for baking with mould: Get a baking spray (I use Easy Bake), and after cake has cooled a bit, use a serated knife parallel to the tin to flatten the bottom. When inverting onto the cooling rack, I put a piece of greaseproof paper bigger than the cake on so that I can transfer the cake easily to the presentation tray
I also just made a trial castle cake for DD's birthday. I used this recipe (not chocolate but had been "sized" for the mould). A few bits of the cake broke off. I had put vegetable oil and a thin layer of flour on the mould before pouring in the mixture. I think I will try the spray next!! How long should I let the cake cool down for? My cake also came out a bit "distorted". Any advice on how to help the mould retain its shape? The mould I have is the one shown on the site above.