Bring 2 of the cups of water to the boil and slowly add the polenta and herbs , whisking all the time. This ensures the polenta won’t form lumps.
Reduce the heat to a simmer, stirring frequently with a wooden spoon.
When the polenta becomes too thick, add the remaining water a little at a time.
Line a tray with cling film and spread the polenta about 1 inch thick using the back of a spoon. Cool overnight. Once cooled, cut into shapes brush with oil and season with salt and pepper and grill on hot grill.
Heat the balsamic vinegar, garlic and sugar in a saucepan. Once the sugar has dissolved, add the asparagus and cook for 3 minute.
To serve: arrange the polenta shapes on serving dishes, top with the asparagus and tomatoes, shave over the parmesan and drizzle with a little olive oil. Garnish with fresh parsley. Serve with lots of fresh crusty bread.