Best Chicken and Wild Rice Casserole Recipe - No Canned Soup

Ingredients

• 1½ cups wild rice blend, cooked according to package directions
• 1½ pounds chicken breasts or thighs, chopped into bite-size pieces
• ¼ teaspoon each salt, pepper, paprika
• 2 tablespoons olive oil, divided
• 2 tablespoons unsalted butter, divided
• 1 yellow onion, diced
• 3 stalks celery, chopped
• 3 carrots, chopped
• 6 cloves garlic, minced
• 8 ounces baby bella/cremini mushrooms, sliced
• 2 cups low sodium chicken broth
• 1 tablespoon cornstarch
• 2 tablespoons unsalted butter
• 1 tablespoon olive oil
• ⅓ cup flour
• 2 cups milk
• 2 teaspoons chicken bouillon
• 1½ teaspoons Dijon mustard
• 1½ teaspoons Worcestershire sauce
• 1 teaspoon each dried parsley, dried basil
• ½ teaspoon each dried thyme, salt, pepper
• 2 cups freshly grated sharp cheddar cheese, divided
• ½ cup freshly grated Parmesan cheese
• ¾ cup panko breadcrumbs
• 1 tablespoon butter