Not quite as good as the slow simmered, stirred constantly, version of polenta but a great hack for a weeknight dinner! We love soft polenta - you can have it "as is", enrich it with lots of cheese and/or butter, pour a sauce over it (burst cherry tomatoes or sautéed mushrooms?) or swirl in pesto or hot sauce...lots of options. You can, absolutely, turn this into solid polenta that you fry or grill, but not quickly. Overnight in the fridge will render your polenta solid enough to slice and fry or cut into fries and bake.
Mix the water/stock, salt and cornmeal in a microwave safe bowl that is larger than you need (it climbs up the sides). Microwave on high for 5 minutes, take it out, stir and microwave for another 3 minutes. Stir in butter, olive oil, cheese or whatever else you might like. Serve hot.