Crockpot Malaysian Sweet Potatoes

3 lbs sweet potatoes, peeled and cut into 1 inch cubes
1 1/2 inches fresh ginger, peeled and minced
1 large onions, diced
1 stalk lemongrass, outer leaves removed, and split lengthwise
1 tablespoon sesame oil
1 1/2 teaspoons tamarind paste
1/4 cup rice wine vinegar
1/4 cup light soy sauce
2 cups orange juice
1 finely grated lemon, zest of
1 pinch ground red pepper (to taste)

Place ingredients into crockpot.

Cover and cook on high for 4 1/2-5 hours or until potatoes are nice and tender.

Remove lemongrass pieces and discard.

Season with salt and pepper, if desired.

Remove potatoes and keep warm; pour liquid from crockpot into a saute pan and reduce until it gets thick and syrupy, then pour over potatoes; serve.