polenta, ready cooked rice

you could try in Italia Autentica in Drogenbos

www.italiaautentica.be/

however most of the big supermarket (ie: Cora, Dlhaize) sell instant polenta, you just have to add boiling water, pinch of salt and cook for 5 minutes, hardly difficult.

It does rather seem self evident that you would pre-cook the polenta or rice yourself and then use it in your recipe!