1) Bring milk and stock to boil in large sauce pan. Gradually add polenta, stirring; cook, stirring occasionally, over medium heat for 10 minutes or until polenta is thick and smooth. Stir in cheese and 1 1/2 oz. of butter until melted. Season to taste; cover to keep warm.
2) Meanwhile, heat remaining butter in a large frying pan over high heat; cook swiss brown and button mushrooms, shallots, and chili, stirring occasionally, until browned lightly. Add oyster mushrooms and garlic; cook, stirring, until softened. Add spinach and nuts; toss well. Season to taste
3) Serve soft polenta topped with mushroom mixture.