Maria,

These are not "balls" but you may boil then mash the sweet potato and make it into balls before you dee fry it. (or just use lemon baller???) I haven't tried this recipe myself but it's close enought to what we will do at home. Maybe it's what you are lloking for? Just a long shot... And good luck hunting if it's not the right one.

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Sweet Potatoes in Syrup

INGREDIENTS
1 lb (500 g) sweet potatoes
2 cups (500 ml) vegetable oil for deep-frying;
use about 3 1/2 oz (100 ml)
5/8 cup or 10 1/2 tbsp (150 g) sugar
2 tbsp (50 g) honey
2 tbsp cornstarch (corn flour), dissolved in 2 tbsp water
2 oz (50 g) haw jelly, diced (I don't know what's this. Maybe it's a translation for some Chinese jelly. However, I think you could/should omit it as I don't recall seeing jelly in this dish.)

RECIPE
Wash and peel the sweet potatoes. Cut into 2 1/2 by 3/4 inch by 3/4 inch (6 cm by 2 cm by 2 cm) strips.
Heat the oil in a wok to 350oF(175oC), or until a 1-inch (25 mm) cube of day-old bread browns in 1 minute when dropped into the oil. Add the sweet potatoes, and deep-fry until brown.
Pour out the oil and add 9 oz (250 ml) of water to the wok. Add the sugar and cook, stirring, until it dissolves. Then add the honey and cornstarch. Cook, stirring, until thickened. Add the sweet potatoes and stir so each piece is coated with the syrup. Place on a plate, sprinkle with the haw jelly, and serve.