In a small bowl, dissolve the sugar in warm water. Sprinkle the yeast on top and let it sit for about 5-10 minutes until foamy.
In a large mixing bowl, combine the flour and salt. Make a well in the center and pour in the milk, melted butter, eggs, and activated yeast mixture. Mix until a dough forms.
Turn the dough onto a floured surface and knead for about 5-7 minutes, or until smooth and elastic. Place the dough in a lightly oiled bowl, cover with a damp cloth, and let it rise in a warm place for about 1 hour, or until doubled in size.
Once the dough has risen, divide it into 2 or 3 portions. Shape each portion into a loaf or roll shape, depending on your preference.
Bring a large pot of salted water to a boil. Carefully add the dumplings and cook for 15-20 minutes, or until they are firm and cooked through. If using multiple dumplings, make sure they have enough space to cook evenly.
Remove the dumplings from the water and let them cool slightly. Slice into thick rounds.
Knedlíky can be served with various Czech dishes, such as goulash or roast pork. They are typically enjoyed with gravy or sauce.
Enjoy your meal!