Add potatoes to a pot, and add cold water up to the point that completely submerges the potatoes. Now let them boil on high heat until they become fork-tender. Once tender discard the water carefully and peel the potatoes.
Use a potato masher or potato ricer to mash them.
Now add all of the seasonings and a little bit of corn starch at a time to make the dough. Flatten a small portion of potato dough, place a cheese cube in the middle, and bring the sides together to make a ball. Shape into a circle using your palms. Continue with the rest of the dough.
Leave them in the freezer for 15-20 minutes before frying.
Heat oil in a pan to 375F. Use a thermometer or fry 1 potato ball to check if the temperature is right. Now add all of the potato balls and fry them for 6-7 minutes or until nice and golden. If you have a smaller pan then fry in batches.
Serve them right away with ketchup or any other condiments.
Potato balls taste best when they are very warm.
Video
Notes
It's very important to rest potato balls in the freezer for at least 15 minutes before frying, or else the cheese will melt and ooze out during frying.