Carefully lower 2 or 3 dough blobs into the oil at a time. Don't crowd them!
For my 4 inchers, I went 3 minutes on the first side, and 2 1/2 minutes on the second side. Use a timer.
If you have smaller ones, try 2 minutes on each side.
They will be golden brown.
Remove with a slotted spoon to the paper towels. After a minutes, roll the warm Berliner in the sugar to coat completely.
Move to the rack to cool enough for filling
(I suggest you put one of the ugly ones in first... make note of how long you left it in. Then cut it open to see if it's DONE. It shouldn't be mushy inside, the dough will be done. If it's mushy, adjust your timing 30 seconds or a minute more or less when you fry the the pretty ones. )
(BTW. kids don't care what they look like... after you've got your timing right, you can fill the ugly ones with jam, and hand them to the kids who are hovering at your elbow waiting for a taste)
Use a pastry bag (Or Ziplock Bag) with a piping tip. Fill it with jam or jelly or cream filling.
Poke into the mostly cooled off Berliner on one side, and carefully squeeze to get the filling inside. You might have to move the tip of the bag around a bit.
If you are like me, and like LOTS of filling... repeat on the other side of the Berliner.
If you are using a few different fillings, you can put a blob on top of the Berliner.
(Although, honestly, I tend to overfill my Berliner, so I can see what kind they are by what is oozing out.)
Eat them FRESH