My purpose in posting is to make a slight addendum to the lovely post of Boyk Sahaab:
http://www.chowhound.com/topics/360462 on Lucknow food. In particular, the excellent kulfi place to which he refers is Prakash Kulfi. Boykji is correct that the sign is in Hindi and perhaps not directly useful to some firangis, but you can ask anyone in Aminabad to point you there. (And if you merely ask for kulfi, you can end up directed to a general store with a freezer case, as I was at first). Prakash is so famous that I saw a (handwritten) advertisement interspersed with the trailers at a cinema in Aishbagh. At Prakash there are two items on the menu: half order and full order. (I usually got a full, but half is pretty substantial). It's Rs18 per half. It's very buttery and hence, as Sri Boyk said, it's delicious.
And since I'm posting: Lucknow has a lot of ice cream, of which some is quite mediocre and some is pretty good. Among the better places is Dinshaw's in Hazratganj, which is on the corner to your left as you enter Janpath market from MG Marg. Another one, whose ice cream is better than its name, is Drooly's on Mandir Marg in Kapoorthala Aliganj, about 100 meters northwest of the main roundabout (churaha) by the Sahara Bhavan building; from the churaha, you walk with the Sahara buildings on your left, and you'll pass by the Aryan restaurant on your right. The same street also has ice cream that's more late than good--in the evenings until midnight daily, there's about 10 ice cream cycle carts on the street. None of it is good (I don't want another "Choc-o-Block" in my life), but it's there. Actually, the popsicles are fine and at Rs5, a much better deal than the Rs20 ice cream novelties.