Pennsylvania Dutch Restaurants
Your title made it sound like you were looking for PA Dutch food, but Donecker's was a fine dining, French influenced restaurant - I'm very sad to see the complex go, but back to your question.
If you are specifically speaking of Ephrata (the town where Donecker's was located) then the only other option is Lily's on Main, but I haven't been there in years, so I don't know if it is still any good. Not too far from Ephrata is Mazzi in Leola.
Otherwise, Lancaster city is your best bet - several fine choices there. John J. Jeffries at the Arts Hotel is wonderful, as is Effie Ophelia, which is BYO. Gusto is a new place that has gotten some good reviews on this board, but I haven't been. Gibralter is also great - seafood, primarily. The Stockyard is a steakhouse, which is not usually my thing, but better than I expected.
This list should get you started, all should have a website except Gusto, last I tried to find one. A search on the board of 'Lancaster' should turn up all of these places, and then some.