Chop the pecans roughly and add to a small bowl. Break the dark chocolate bar into small pieces by hand. Mix the cinnamon powder and brown sugar and set aside
In a large mixing bowl sieve, the flour, and the sugar - just to ensure no lumps go into. Add the baking powder and baking soda, softened unsalted butter, vanilla and eggs did not use an electric mixer just used a large spatula and mixed the whole thing together well until a proper thick mix was formed. Then I added in the soured cream and mixed well again
Now pre-heat the oven to 180 degree Celsius
Grease a 12'' cake tin using a generous blob of the unsalted butter and pour enough cake mixture to make a thin layer then sprinkle some of the pecan mixture. Repeat at least 3 times until all the cake and pecan mixture is alternatively used up
Bake in the centre of the pre-heated oven at 18 degree Celsius for one hour
Check using a toothpick or a thin knife to check if the cake is done by inserting it into the middle of the cake. If it comes out clean then the cake is done
Place the cake tin on a wire rack and allow to cool completely before releasing the removable base of the tin
Serve with freshly brewed tea
Stores well in the refrigerator for at least a week in an air-tight tin