(Total Time: 35 MINS| Serves: 8) Ingredients: For Casserole: 2 tbsp. butter 1 thinly sliced yellow onion Salt, to taste 8-ounce sliced button mushrooms 1¼ pounds trimmed and halved green beans 2 finely chopped garlic cloves 1 tsp Dijon mustard ½ cup homemade vegetable...
