This Roman rosemary polenta, baked and cut into squares, is wonderful on its own or with any accompaniment, but is particularly great a mound of orange and chili-flecked cavolo nero. First, the cheesy, herby polenta is cooled to set, then broiled or baked with more cheese on top. —Ed Smith | Rocket & Squash
Put the milk and 2 of the rosemary sprigs in a large saucepan, bring to a rapid simmer and cook for 5 minutes. Remove from the heat and leave to infuse for 25 minutes, then discard the rosemary.
Sprinkle the polenta into the pan in a slow, steady stream, stirring continuously. At first it will seem as though there’s far too much milk, but after 3–5 minutes the polenta will swell and thicken. Continue to stir vigorously, almost without interruption, for 10–15 minutes over a low heat. Once the grains are less visible and the polenta starts to become smooth, reduce the heat to very low and cook for 10 minutes more, beating it frequently. Add some extra water to loosen the mixture if necessary.
Meanwhile, line an 8x8-inch baking tray with parchment, and grease the paper with 1 tablespoon oil. When the polenta is cooked, smooth and slick, add 40g (about 3 tablespoons) of the butter and 60g (1/2 cup) of the Parmesan and beat well, season with salt, then pour it into the lined tray. Use a palette knife or the back of a spoon to push and smooth the polenta into the corners to an even depth of around 1-inch. Leave to cool, then put in the fridge to set for at least 30 minutes or overnight.
Once the polenta has cooled and set, turn it out onto a clean work surface and cut into 2-inch squares. Place these, smooth-side up, on a larger lightly oiled baking tray (or two), leaving a little space around them. Preheat the oven to 482° F (250° C).
Strip the leaves from the remaining rosemary and chop them very finely. Melt the remaining butter and pour or brush this over the polenta squares. Sprinkle the rosemary over the top, then finish with the remaining Parmesan. Bake for 15 minutes, or until golden. Allow to cool and firm up for 5 minutes before serving.