In a large pot, sauté garlic in just a little drizzle of olive oil. Add water (or broth), salt, and polenta, stirring well. Bring to a boil, then reduce to a simmer. . Simmer for about 40 minutes, or until the polenta starts to come together and pull away from the pot. Stir occasionally (every 5 minutes or so) to avoid clumps. When ready, stir in the cream.
Meanwhile, warm a pan over medium heat. Add butter and onions. Caramelize onions over low heat, stirring occasionally for about 20-30 minutes. Deglaze the pan as necessary with balsamic vinegar (you can use any vinegar, or even wine!), and add the mushrooms. Sauté over low heat until soft and caramelized.
When polenta is almost done, add chopped swiss chard to mushrooms and stir together. Cook just until wilted, about 1-2 minutes.
Divide polenta among 4 plates (or bowls) and spoon veggie sauté over each one. Top with freshly grated parmesan cheese, black pepper, and any herbs you like (fresh rosemary and sage are both delicious here). Enjoy!