In a large mixing bowl, use an electric hand whisk to cream together the butter, sugar and vanilla. Add the eggs, one at a time, whisking each one in completely before adding the next. If it starts to curdle, add a tablespoon of flour and carry on whisking. Add half of the flour, and mix through, then add the remaining half and the buttermilk.
Spray or brush the inside of your bundt tin with vegetable oil. Pour the cake mixture into the tin - there should be a 3cm gap at the top. Cover the top of the tin with baking paper and then foil, and fold it loosely around the edges.
Bake the cake for 1 hour and 15 minutes, or until a skewer comes out clean. Let it cool in its tin for 10 minutes, then carefully turn it out onto a wire rack to cool fully.
To make the icing, drain the cream cheese of any liquid and pat it dry. Use an electric hand whisk to beat together the softened butter and cream cheese. Beat it until it’s just combined and then stop. Add in the icing sugar and use a spoon to stir it together, then carry on with the electric whisk until it’s smooth and holds stiff peaks. Don’t over mix it. Cover the bowl with cling film and put it in the fridge until you’re ready to ice the cake.
When the cake is fully cool, give the icing a good stir then spoon it into a piping bag fitted with a large petal decorating tip.
Put the cake onto a decorating wheel and turn it while piping ribbons along the ridges of the cake. Dust very lightly with icing sugar, then serve.