I used this ready-made polenta from Tesco which did the job perfectly. Alternately, you can prepare your polenta chip mix yourself using step 2 of this BBC Good Food recipe. I jazzed mine up a tiny bit adding some dried oregano and rock salt before baking. I suggest rock salt over table salt as the cured meat is quite salty so the little bursts from the chunky salt clusters is more pleasant.
Wrapping the prosciutto around the polenta is a little bit of a faff as it tends to break in parts so you don’t really get a nice long piece to wrap around. The polenta can also be quite delicate once you’ve chopped it into chips, so handle them with care when it comes to turning them over half way through their cooking.
I found mine took just over the suggested 30 minute cooking time, but I wanted them to be really golden… like me.