This cake is a sort of Anglo-Italian amalgam. The flat, plain disc is reminiscent of the confections that sit geometrically arranged in patisserie windows in Italy; the sharp, syrupy sogginess borrows from the classic English teatime favorite, the lemon drizzle cake. It is a good marriage: I love Italian cooking in all respects save one - I find their cakes both too dry and too sweet. Here, though, the flavorsome grittiness of the polenta and tender rubble of ground almond meal provide so much better a foil for the wholly desirable dampness than does the usual flour.
But there is more to it than that. By some alchemical process, the lemon highlights the eggy butteriness of the cake, making it rich and sharp at the same time. If you were to try to imagine what lemon curd would taste like in cake form, this would be it.
Although I am greedily happy to slice and cram messily straight into my mouth, letting damp clumps fall where they will, this cake is best eaten - in company at least - with spoon and fork. Either way, consider it a contender for teatime comfort and supper-party celebration alike.
For the cake: Line the base of your cake pan with parchment paper and grease its sides lightly with butter. Preheat the oven to 350 degrees F.
Beat the butter and sugar till pale and whipped, either by hand in a bowl with a wooden spoon, or using a freestanding mixer.
Mix together the almond meal, polenta and baking powder, and beat some of this into the butter-sugar mixture, followed by 1 egg, then alternate dry ingredients and eggs, beating all the while.
Finally, beat in the lemon zest and pour, spoon or scrape the mixture into your prepared pan and bake in the oven for about 40 minutes. It may seem wibbly but, if the cake is cooked, a cake tester should come out cleanish and, most significantly, the edges of the cake will have begun to shrink away from the sides of the pan. Remove from the oven to a wire cooling rack, but leave in its pan.
For the syrup: Make the syrup by boiling together the lemon juice and confectioners' sugar in a smallish saucepan. Once the confectioners' sugar has dissolved into the juice, you're done. Prick the top of the cake all over with a cake tester (a skewer would be too destructive), pour the warm syrup over the cake, and leave to cool before taking it out of its pan.
Make Ahead Note: The cake can be baked up to 3 days ahead and stored in airtight container in a cool place. Will keep for total of 5 to 6 days.
Freeze Note: The cake can be frozen on its lining paper as soon as cooled, wrapped in double layer of plastic wrap and a layer of foil, for up to 1 month. Thaw for 3 to 4 hours at room temperature.