Cook kielbasa as you normally do.  I boil mine.  Set aside.
 
In frying pan sauté 1 large onion with 1-2 sticks of butter.  Add 1 head of chopped cabbage.  Keep stirring till done.  Set aside.
 
In food processor almost puree 2 large potatoes.  Add 1 egg.  Then add flour to make a very soft & stick dough.
Have a big pot of water boiling.
Dump dough onto a plate & with knife or  I use my hands pinch off very small amounts of dough into boiling water.  You might have to do this in 2 batches.  It depends on how much you make.  When I  make it I use 3 large potatoes.
When done rinse very good.  In big pot mix everything together.  You can add more butter* if needed.    Of course add a lot of salt to cabbage & dough.
 
* You all know me & my butter.