Bring the broth to a rapid boil in a large pot over high heat.
Add the lemon pepper, salt, basil, bay leaves, garlic powder and pepper.
While waiting for the broth to boil, in a separate bowl, whisk together the flour, baking soda and salt.
Stir in the melted butter and 3/4 cup buttermilk until a dough forms.
Turn the dough out onto a clean work surface generously dusted with flour.
Roll the dough to 1/8 inch thick, then cut into 2-inch squares or rectangles.
Drop dumplings into the boiling stock and allow to boil, while stirring frequently, for approximately 15 minutes, until dumplings are cooked through.
After the dumplings are cooked, stir in the chicken and heat through while stirring.
If the soup needs to be thickened, mix together the 1/4 cup buttermilk and cornstarch in a small bowl and slowly stir it into the soup until it reaches the desired consistency.