White Chocolate and Thyme is a very promising combination. I moved on this and added one more special flavour to the cake: dried figs. It gives a nice, crispy texture to the sponge and a a few drops of lemon juice make a perfect balance.
After the first version I tried a new combination with dark chocolate ganache on the top of the cake. It was a luxury dessert, very rich but perhaps was too much flavour in one cake.