Bottom-Friendly Green Bean Casserole

Name: Bottom-Friendly Green Bean Casserole
Prep time: 20 min
Cook time: 1 h 15 min
Total time: 1 h 35 min
Cuisine: American
Ingredients: 2 lb. green beans; salt to taste; 1 lb. oyster mushrooms; 2 tbsp olive oil; 6 tbsp butter (or vegan butter); 1 tsp thyme leaves, ~5-6 sprigs; 3 tbsp all-purpose flour; 2 unflavored, unsweetened non-dairy milk; 2 tbsp olive oil; 2 tbsp butter; 4 garlic cloves, roughly chopped; 2 shallots, roughly chopped; 1 C panko bread crumbs; 1 tsp salt; 2 tsp onion powder; 1 tsp garlic powder