Peel a bunch of jewel or garnet yams (the bright orange sweet potatoes). I soak them in cold water before I cut them. This keeps them from oxidizing and discoloring.
Cut them about 3/4 inch thick on a diagonal slice. Par cook by boiling them, just a little, don't let them get soft. Maybe about 5-7 minutes.
Lay them in a glass pan slightly overlapped in nice rows like a tray of cookies.
In a sauce pan, saute:
An inch or three of fresh ginger - grated/finely chopped
2-3 cloves of garlic, minced
1-2 shallots, minced
1/4 cup olive oil
Don't over cook garlic, so keep heat medium low.
1 cup soy sauce
1/3 cup rice vinegar
1/3 cup white wine/sake/other Asian white wine
1/2-1 cup brown sugar
juice from one orange
Zest from half orange
Spice it up with anything you have. Cayenne, red pepper flakes, sriracha, it's all good.
Now, you have to start tasting it. If it's too tart, add more sugar. If it's too sweet, add a bit more vinegar. If it's too salty, add more sugar and/or wine. Have fun. There's really no RIGHT way - it's all about taste.
Once you have the taste right, mix about 2 Tb corn starch in 1/3 cup cold water or chicken stock. slowly add mixture to sauce, cook until thickened.
Pour sauce over sweet potato slices in pan.
Hope this works out for you. I promise it will woo many folks into a deep and long-lasting love affair with sweet potatoes.