In a medium saucepot melt the butter with the oil over med heat. Add the onion and sauté until it begins to turn golden.
Add the stock, peppers, and herbs and bring to a boil.
Gradually sprinkle in the grits, stirring. When all the grits have been added turn the heat down and cook covered, stirring occasionally for 15 minutes, add the peas the last 5 minutes of cooking
Remove the pot for the heat and stir in the parsley and the mushrooms and the cheese.