Preheat oven to 180 degrees Take a 30cm cake pan and line in with grease-proof paper. On top on the paper sprinkle 10g of the brown sugar evenly across the surface. Take the orange slices and arrange them in your desired pattern on top of the sugar.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time.
Fold in the flour and spices until fully incorporated, then carefully spoon the mixture on top of the orange slices and spread evenly.
Bake in the middle of the oven for 45 minutes, until a skewer comes out the centre clean. Leave to cool for 10 minutes, then turn out on to a plate.