Preheat the oven to 350°.
Cook the green beans in a large pot of boiling salted water until al dente or slightly crunchy. Strain and set aside.
In a large sauté pan over medium heat add in the bacon and cook until crisp. Set the bacon aside and cook the mushrooms, onions and garlic in the bacon fat for 6 to 8 minutes or until caramelized.
Next, add in the cream and cook over medium-low heat until it becomes thick like alfredo sauce.
Combine the mixture with the green beans. Mix in thyme, salt and pepper and transfer to a casserole dish.
Sprinkle the bread crumbs over top and bake for 25 to 30 minutes.