Heat oven to 160C/140C fan/gas 3.
Grease and line a 22cm round springform
cake tin with baking parchment. Sift the
flour, spice and baking powder into
a bowl and crumble in the sugar. In a
separate bowl, beat the eggs with the
orange zest and juice, then pour in the
oil. Add the marrow and 150g of the
pecans to the oil mixture, then beat
into the flour until combined. Tip into
the cake tin, smooth the top and bake
for 1 hr 20 mins, or until a skewer comes
out clean. Leave to cool for 30 mins in
the tin before removing and placing on
a wire rack to cool completely.
While the cake is cooling, make the
icing by beating all the ingredients
together. When the cake has cooled,
use a spatula to spread the icing over
the top. Sprinkle over the rest of the
pecans to decorate and serve.