Simmer 1 cup orzo to 2-3 cups broth until liquid is absorbed. Add a pinch of salt to the broth. Once cooked stir well and set aside.
Saute mushrooms in oil and butter until nicely browned. Add a pinch of pepper at the beginning and salt at the end.
In a serving dish mix together cooked rice, orzo, half the mushrooms and half the parsley. Taste and add salt and pepper if needed. Add remaining mushrooms to the top and sprinkle with remaining parsley.