Heat butter and oil in a large pot or dutch oven over medium high heat until melted. Saute onion for 2 to 3 minutes until softened. Cook garlic until fragrant, about 1 minute
Add mushrooms and 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 chicken broth, mix again and bring to a boil. Reduce heat to low-medium heat, season with salt, pepper and bouillon cubes.
Cover and allow to simmer for 10-15 minutes, stirring, until thickened
Reduce heat to low, stir in half and half. Allow to gently simmer (do not boil). Adjust salt and pepper to your taste. Mix in parsley. Serve.