Heat butter and oil in a large pot over medium-high heat until melted. Sauté onion for 2 to 3 minutes until softened. Cook garlic until fragrant, about 1 minute.
Add mushrooms and 2 teaspoons thyme, cook for 5 minutes. Pour in wine and allow to cook for 3 minutes.
Sprinkle mushrooms with flour, mix well and cook for 2 minutes. Add stock, mix again and bring to a boil. Reduce heat to low-medium heat, season with salt, pepper and crumbled bouillon cubes.
Cover and allow to simmer for 10-15 minutes, while occasionally stirring, until thickened.
Reduce heat to low, stir in cream or half and half. Allow to gently simmer (do not boil). Adjust salt and pepper to your taste.
Mix in parsley and remaining thyme. Serve warm.