recipe I found on the Cake Baker website - which, unusually these days, gives measurements in ounces.
200g caster sugar
100g ground almonds
200g instant polenta
1 orange, zest and juice
Cream the butter and sugar. Beat in the eggs. Fold in the almonds, polenta, and lemon juice. You should have a stiff batter.
I cannot give very helpful advice about oven temperatures. The recipe advises you use an eight-inch (20cm) cake tin, whereas the one in the picture has a base of 15.5cms. That was one reason why my cake took a lot longer to set than the 20-25 minutes specified; another may be that my oven is behaving a bit strangely, often failing to reach the temperature on the dial.
I started cooking the cake at gas mark 5/190C (but at what may have been a good deal cooler than that). After half an hour, the centre was runny. I turned up the dial to 6/200C. Fifteen minutes later, I moved the cake to a higher shelf. It took an hour in total.
You need cream or ice cream as an accompaniment, to offset the dry graininess of the polenta.
Or perhaps this Telegraph version, with less polenta but more ground almonds, is worth trying. Like many polenta cake recipes, it includes baking powder - which usually contains gluten. I don't think my cake suffered from the lack of it.