Espaço Edla is close to the train station in Sintra. They always have some paintings/watercolours in exhibition and the place aims at being something between modern, vintage and rustic: lots of white, comfy seats and pillows, stone walls and gourmet products (some not gourmet, but stemming straight from the Portuguese typical food products).
They have sandwiches, toasties, scones and several sweets, besides a daily lunch menu. The staff are nice and helpful, although the service can sometimes be a bit slow. Then again, I can't imagine why anyone would go there to be eating in a hurry.
The food is good, but if you have a sweet tooth I'd highly recommend the following exercise: look at the sweets display window; close your eyes; go "Eeny, meeny, miny, moe"; eat the sweet that destiny picked for you. Enjoy!