Ella's Chicken Hash

Source: Danny Wilser, owner of Ella's, San Francisco, California

Serves 6

2 pounds russet potatoes
2 pounds Yukon gold potatoes
1/4 cup yellow onion, diced
1 tablespoon fresh sage, chopped
1 tablespoon fresh parsley, chopped
1/2 tablespoon fresh thyme, chopped
1 extra large egg
1 tablespoon stone-ground mustard
Salt and pepper to taste
2 to 3 cups cooked, shredded chicken
1/4 cup canola or other vegetable oil, plus
    about 1 tablespoon for saut