After making all that lemon curd I had lots of egg whites to use up. I did use some to make the meringue for the lemon meringue pie, but there is only so much meringue a girl can eat (unless you are my sister!). Last time I had this problem a quick Google suggested Angel Food Cake as a possible recipe. This is popular in America and is a fat free cake where the egg whites are whipped and folded with flour and cream of tartar and then baked in a 'tube pan' to help it rise and keep the its shape. As I didn't have any cream of tartar I went looking further and found a recipe for a cake called Mumavalgekook, which is an Estonian cake very similar to Angel Food Cake except that it has melted butter folded in to the mixture which gives it a little bit of extra stability when baked. The recipe for Mumavalgekook I use is from Nami-Nami, another fantastic food blog. Essentially you whip the egg whites (I did using my Kenwood of course) and a little sugar to make a fairly relaxed meringue, and then you fold in the rest of the sugar, flour and melted butter along with a little vanilla. You have to do this quickly and gently so as not to lose all the air in the mix, and it feels very different to a normal cake batter. I always get slightly worried at this point because you can hear all the bubbles in the egg whites bursting as you fold the dry ingredients in, and you do lose some volume. However, as long as you fold just enough to incorporate the dry ingredients and the butter in and bung it straight in the oven it seems to work fine.
When baked and cooled it had a very springy, but light texture with a nice sugary crust, a bit like the one on boudoir biscuits (ladies fingers). It keeps very well for a few days, and is even nice toasted with a bit of extra butter on. Or you can sandwich a couple of bits together with leftover lemon curd!