Tucked behind King's Cross St. Pancras on the edge of Granary Square is Caravan Roastery. Housed in an old grain store, Caravan keeps with the building's tradition and has a large, open plan dining room, with an open grated divider separating the dining space from the kitchen space, but still allowing you to watch as the chefs carefully prepare each dish. They also have a coffee roastery on site, making their coffee some of the freshest pick me ups you can get.
All of their food is locally sourced and tastefully refined, focusing on highlighting seasonal ingredients. The phrase good things come in small packages applies to the food here, as the portions are a bit smaller than your average restaurant. The food, however, is anything but average.
Their cocktails aren't too bad either... I recommend the pomegranate bellini.
You might be hard pressed to get a table at their infamous weekend brunches, as they take no reservations for these, so the wait can climb to two or three hours. However, they do the same brunch on weekdays, but it only lasts until 11am instead of all day (but you now have the added benefit of being able to make a reservation and avoiding the weekend crowds).
Caravan's spacious bar has almost everything one could want.