Preheat oven to 200c
Grease a 28cm round cake tin and line base and sides with baking paper
Place butter, sugar and vanilla seeds in the bowl of an electric mixer fitted with a whisk attachment.
Whisk on low speed until pale and creamy.
Add eggs one at a time, making sure they are completely incorporated before adding the next.
Add sour cream in two batches, and then add the flour in two batches, until well combined.
Scoop the mixture into the prepare cake tin. Arrange the plum half’s evenly on top.
Bake for 55 minutes to 1 hour 15 minutes, or until a skewer comes out clan when inserted into the center of the cake.
Remove from oven and allow to cool in the tin for 10 minutes before turning out onto a wire rack to cool completely.
Best eaten as soon as it has cooled, can be stored in airtight container for up to 3 days.
Serve with crème fraiche or ice cream, praline, more plums and dusted with icing sugar.
250g unsalted butter
350g caster sugar
1 vanilla bean, split and scraped
200g sour cream
300g self-raising flour, sifted
4 ripe plums, halved and destoned
Creme fraiche or ice cream
Icing sugar for dusting