Rustici are small pastries that look very much like mini pies. They start cropping up in bars and pizzerias once you enter the province of Brindisi, but it is Lecce where they become ubiquitous.
The pastry itself is filo, which reflects the connection with Greek food and culture in this part of Italy; the Salento peninsula is where the food noticeably starts to mix Greek and Italian influences. The inside is pure Italian: some mixture of cheese, usually mozzarella, and tomato. Besciamel sauce is a popular, if hazardous, filling... Beware the super-heated besciamel rustico if you're tempted to bite down into the thing. Dangerously hot, and liable to end up all over you too.
Deceptively filling, the rustico also makes a very cheap lunch. At around one to two euros, you'd only want two at most. Delicious. Don't miss out on trying rustici in their hometown of Lecce.