I am missing the syruplike top on my Clementine Cake and then I noticed what isn't really clear to me: are the clementines mixed with the almond and eggs etc (which I did) or are they put on top last? I'd love to know how I'm getting that top layer in a next try.
Nigella's Clementine Cake (from HOW TO EAT) is a moist gluten free cake that is perfect as a cake to serve over Easter. As the cake cools the top becomes slightly sticky, almost as if it had a syrup brushed over the surface. It will be more noticeable once the cake has been cooled and stored in an airtight container overnight and it may be that you just need to let the cake sit overnight. The cake batter is made from mixing the cooked and pureed clementines with eggs, sugar, ground almonds (almond meal) and baking powder. The clementines are not put on top afterwards.
If the top is a little dry even after storing overnight then we suspect that the cake may have been slightly over baked and did not have enough moisture in the cake to give the syrupy top. The cake should be baked until firm to the touch and a cake tester inserted into the centre should come out clean. The cake needs to be covered part way though baking, usually at around 40 minutes, as this will prevent the top from colouring too much but will also help to retain some moisture in the cake. The oven temperature of 190c is also for a conventional oven and may need adjusting for a fan or convection oven. If the top remains dry on this particular cake then you could add a finishing coat of glace icing made from icing (confectioners') sugar mixed to a paste with a little clementine or orange juice.