This classic French cake, the Quatre-quart, is also known as a pound cake elsewhere. It's a simple sponge that can be enjoyed plain, but I've experimented and added diced pears, vanilla extract, lemon zest, and even orange flower water for flavour. But really, we seem to like the plain cake the best!
I include baking powder to make the cake airy, but sometimes, when I feel ambitious, I omit it, separate the eggs and beat the whites to give the cake its lift.
If you don't have a 24cm tube tin, you can also use two 23cm round cake tins; two 20cm round cake tins; or one 25cm Bundt cake tin. Bake at the same temperature and adjust baking time as needed.