Grease and line a 20cm springform tin.
Preheat oven 180C/gas4
It's an easy cake to make:
Put 175g soft butter or marg in the bowl of an electric mixer; add 175g soft brown sugar, 2 beaten eggs, 175g sr flour, 1/2 tspn baking powder and 1 tspn cinnamon, and beat together till nice and creamy.
You need 450g plums, halved and stoned. [ If they're not really ripe, put them in a dish in the oven sprinkled with 2 tbspn granulated sugar and bake them for about 20 mins till they've softened.]
Put the plums, cut side up, on top of the cake batter and make the topping.
Melt 50g of butter, add 50g sr flour, 1 tspn cinnamon, 25g oats and 25g flaked almonds and mix together.
Put the topping in blobs over the plums, trying to cover all the cake.
Bake for 11/4 hours till the top's golden.
You can see that my cake sank down in the middle - not sure why, as I didn't open the oven door at all - but this didn't stop it being delicious!
This shows what I mean about the top being rather like flapjacks.
We had a slice as a dessert with a blob of creme fraiche. I loved the textures - the soft cake and fruit and the chunky topping with the nuts and oats.