Prepare the polenta: In a large pot, bring water and salt to a boil. Gradually whisk in the cornmeal, reduce heat to low, and cook for 15–20 minutes (for medium-coarse polenta), stirring frequently until thick and creamy. Stir in olive oil, cover, and set aside.
Sauté vegetables: Heat olive oil in a braising pan over medium heat. Add diced onion and grated carrot, sauté for 5 minutes until softened. Add bell peppers and cook for another 5 minutes.
Cook mushrooms: Add sliced mushrooms to the pan. Cook for 8–10 minutes until they release their liquid and begin to brown. Stir in minced garlic, sweet paprika, smoked paprika, and thyme, and cook for 1 minute until fragrant.
Simmer stew: Crumble the vegetable broth cube into the pan, add diced tomatoes, drained beans, and ½ cup water. Stir well, cover, and simmer for 10–15 minutes until flavors meld. Season with salt and pepper.
Prepare paprika sour cream: In a small bowl, mix vegan sour cream with sweet paprika, lemon juice, and a pinch of salt. Set aside.
Serve: Spoon a generous portion of polenta into each bowl. Top with the mushroom and bean stew, drizzle with paprika sour cream, and garnish with chopped parsley and a sprinkle of paprika.