Combine the first six ingredients in a pot and bring to a boil. Add the polenta in a steady stream, stirring constantly, and reduce heat to a simmer. Continue to cook and stir until it has absorbed most of the liquid and has a creamy texture.
Add the vegetables and cheese and cook for 1 more minute.
Whip the marjoram into the polenta and when it is well distributed, pour the polenta into an 11 glass pie plate.
Once the polenta cools it can be cut into wedges to be served either hot or cold.This polenta makes a quick and delicious accompaniment for grilled meat or fish, yet is substantial enough to be a light lunch when topped with fresh tomato and grated Parmesan cheese.