Maybe a little variation from the "metrowest" category, but so good I had to comment... besides, from Natick it's only about a 20 minute drive if you avoid traffic.
Anyway, the Grasshopper in Allston has some of the best food in the world. It's cold in the winter (maybe being a vegan restaurant and all they're trying to be environmentally conscious but I think eating with a jacket on might be taking things too far... and this from someone who refuses to use paper towel and keeps her house a toasty 64) and the atmosphere might not be the best, but like I said, possibly some of the best food in the world, so well worth it (and you can always get takeout).
They give you tea - hey, you need something to warm up - and the hot and sour soup, spicy bean cakes, and No Name (some sort of deliciously fried tofu thing) are musts. It's a HUGE menu with lots of typical (and totally different) Chinese dishes but they are all vegan and all amazing (some healthy but don't get the idea that because it's vegan it's all yucky tasting green stuff with no sauce - there's plenty of fried stuff here too). Excellent shakes, smoothies, and desserts also.
So next time you decide to head past Wellesley center or want to pick up take out on the way home from Boston (not that Natick and Wellesley lack good restaurants.... ummm, Lemon Thai, Yama, Dah Mee, Papa Razzi), give it a try!