Grand Hotel Sweet Potato And White Corn Soup

Source: Grand Hotel, Mackinac Island, Michigan

1 large white onion, diced
1 cup white corn kernels, fresh or frozen
2 tablespoons vegetable oil
1/3 cup white wine
3 large baked sweet potatoes peeled, diced
5 cups chicken stock
1/4 cup mixed fresh thyme plus basil and tarragon
1 tablespoon finely chopped pickled ginger
Salt and pepper
1 cup half-and-half
1/4 cup diced cooked celery
1/4 cup diced cooked white potatoes
1/4 cup cooked white corn kernels
Chopped chives
Croutons

Saut