Melt the butter in a large sauce pan over medium heat, add the onions and mushrooms and cook until the mushrooms have released their moisture and it has evaporated, about 15-20 minutes.
Add the garlic and thyme and cook until fragrant, about 1 minute.
Mix in the flour and cook for 2-3 minutes.
Add the Ruby Red wine and deglaze the pan.
Add the broth and beef, bring to a boil, reduce the heat and simmer for 15 minutes.