Located on 7th Ave in Park Slope, the Walk-In Cookbook is a storefront biz offering the same sort of service as online - you choose recipes you'd like to make and they provide the portioned out ingredients. They source high quality ingredients, local and organic when possible. Many of the items are kept loose and packaging, when used, is minimal. By shopping in-store you can also decline any ingredients you already have at home.
Gluten-free recipes are clearly marked (orange ribbon at lower right):
It's also just a lovely space to shop in.
In addition to the meal kits they also offer individual grocery items like olive oil, ice creams, and gluten-free baking mixes: