Smoky Green Bean Casserole

In a 4-quart Dutch oven cook green beans in lightly salted boiling water for 3 minutes. Drain beans and pour into a very large bowl of ice water. Drain again. Transfer to a very large bowl.

In a large saucepan cook and stir mushrooms and garlic in hot oil over medium to medium-high heat until soft and beginning to brown. Stir in soup, cheese, milk, and mustard until combined. Add to bowl with beans. Add red pepper and water chestnuts. Toss to combine.

Spoon half of the bean mixture into a 4-quart slow cooker. Top with half of the french-fried onions. Repeat layers.

Cover and cook on low-heat setting for 4-1/2 to 5 hours or on high-heat setting for 2-1/4 to 2-1/2 hours.