1 Boil 650 ml (approximately 2 3/4 cups) of water in a pot and add salt. Sprinkle in cornmeal while stirring and bring to a boil. Cover and cook on low heat for about 12 minutes, stirring constantly.
2 Meanwhile, rinse scallions, trim and cut into 1 cm (approximately 1/2-inch) thick pieces. Trim oyster mushrooms and cut into 1 cm (approximately 1/2-inch) wide strips.
3 Heat the olive oil in a pan. Add oyster mushrooms and scallions and cook over medium heat for about 3 minutes.
4 Rinse rosemary, shake dry, pluck off the needles, chop coarsely and add to the vegetables. Season with salt and pepper and fry for another 2 minutes.
5 Grate Gouda and sprinkle over the mushrooms. Season to taste with salt and serve with polenta.