Creamy Green Bean Casserole from Scratch - Recipe Tweets

Ingredients

• 1 medium onion
• 1/2 cup all-purpose flour
• 3/4 cup panko breadcrumbs
• 1/2 teaspoon salt
• 1/4 teaspoon ground black pepper
• 1 large egg
• 1 Tablespoon milk
• 1 Tablespoon + 1 teaspoon salt, divided
• 1 pound fresh green beans, rinsed, ends trimmed, and halved
• 2 Tablespoons unsalted butter
• 8 ounces sliced mushrooms*
• 2 cloves garlic, minced
• 3/4 cup chicken or vegetable broth
• 1 1 1/4 cups half-and-half