Treacle, E2 7RG
Treacle does gorgeous cupcakes. Buy a box and sit in the park round the corner to eat them if the weather is nice. Be warned it's only open on Sundays though and there's no seating in the shop.
Opening hours taken from the Treacle website, May 2007.
OS X co-ord: 534006 OS Y co-ord: 182933 (Latitude: 51.528904 Longitude: -0.067942)