Heat the oil in a very large and wide skillet set over medium-high. Add the onions, mushrooms and garlic and cook until tender and the liquid from the mushrooms has evaporated, about 6 to 7 minutes. Mix in flour, rosemary or thyme and paprika and cook 2 minutes more. Slowly mix in the wine. Cook until the mixture thickens, and then slowly mix in the stock. Bring to a simmer, and simmer until a thickened sauce forms around the mushrooms. Season the stroganoff with salt and pepper. Top the servings of the stroganoff with a dollop of sour cream and a sprinkling of parsley.