In a large bowl, combine the grated potatoes, all-purpose flour, salt, and egg. Mix until you get a thick, sticky dough.
Bring a large pot of salted water to a boil.
Using a halušky maker or a colander with large holes, press the dough through the holes directly into the boiling water.
Cook until the halušky float to the surface, about 2-3 minutes.
Remove with a slotted spoon and transfer to a bowl. Keep warm.
In a small bowl, mix the bryndza cheese and sour cream until smooth and creamy. Set aside.
In a skillet, cook the diced bacon over medium heat until crispy.
If using, add the finely chopped onion and sauté until translucent and caramelized.
Remove from heat and set aside.
In a large serving bowl, toss the hot halušky with the bryndza sauce until well coated.
Sprinkle the crispy bacon (and onions, if using) over the top.
Enjoy your meal!