Just perusing the website of Ottolenghi, the closest I can think of in DC is Dean & DeLuca, in Georgetown (http://www.deandeluca.com/). No idea if they deliver, though.

If you are looking for food to be delivered, consider foodler.com and grubhub.com for extensive menu aggregator sites.

There are lots of good options for picking up food, but I'm presuming you don't want to trek across the city; a location would be good. Also check donrockwell.com for extensive reviews of places across the city.