Grease and lightly flour a 1.4 litre (6 cup) fluted bundt tin. Preheat the oven to 180C/160C fan/gas 4.
Put the butter and sugar into a bowl and beat well using an electric mixer until the mixture is very light and fluffy. Add the eggs a little at a time, beating well between each addition. Add a little flour if the mixture starts to separate. Add the vanilla extract.
Mix together the flour, baking powder and salt and stir half into the butter mixture together with half the soured cream. Beat well together.
Add the remaining flour and soured cream and mix well. Spoon into the prepared tin and spread level.
Bake in the oven for 35-40 mins. When cooked remove from the oven and leave to cool in the tin for 5 mins.
To make the glaze put all the ingredients into a small pan and heat until the butter has melted. Bring to the boil then reduce the heat a little and simmer for 3 mins. Remove from the heat and allow to cool and thicken.
Turn the cake out onto a wire rack over a tray. Pour or brush half of the glaze over the cake. Leave to soak in. Then pour the remaining glaze over the cake. Leave until completely cold before serving.