Fresh Green Bean Casserole - The BakerMama

Ingredients

• 2 medium yellow onions, halved and thinly sliced
• 1/4 cup all-purpose flour
• 2 tablespoons panko bread crumbs
• 1 teaspoon kosher salt
• 1-1/2 pounds fresh green beans, trimmed
• 2 tablespoons butter
• 1 cup milk
• 1 cup chicken broth
• 1 tablespoon Italian seasoning
• 1 teaspoon salt
• 1/2 teaspoon black pepper
• 1 teaspoon butter
• 2 cloves garlic, minced
• 1 (8-ounce) package sliced fresh mushrooms
• 1 (15-ounce) can petite diced tomatoes, drained well