My colleague always talked about "BBQ tonight" in Karachi. He doesn't cover Pakistan anymore but remembers the restaurant with great affection.

For Lahore, Time Out once featured this brothel turned restaurant as one of the best dining experiences. From the internet I found the following:

Location: Taxali Gate, Adjacent to Badshahi Masjid, Walled City, Lahore

Description:
Located in lahore’s famous red light area, heera mundi (diamond district), this restaurant was the brain child of Iqbal Hussain, a painter and the son of a prostitute who worked this area in the past.

Coocos Den used to be a brothel that was converted into a restaurant by the son of a prostitute that worked there. He is now a famous professor and artist. His paintings show the human and emotional side of women working in brothels and he has brought awareness to the public of the atrocities that happen to prostitutes in Lahore.

Alternatively in Lahore visit "Food Street" in the evening when the street in turned into one long cafe.