In a large saucepan, bring vegetable broth to a gentle boil
Slowly whisk in the cornmeal, stirring constantly to avoid lumps
Reduce heat to low and cook for 15-20 minutes, stirring frequently
Add milk, butter, Parmesan, salt, and black pepper, stirring until smooth
Remove from heat and keep warm
In a skillet, heat olive oil over medium heat
Add sliced mushrooms and sauté for about 5 minutes until they start to brown
Stir in garlic, salt, and black pepper, cooking for another 2 minutes until fragrant
Drizzle with balsamic vinegar if using, then remove from heat and stir in fresh parsley
Spoon the creamy polenta onto plates and top with the garlic mushrooms
Serve warm and enjoy