Not many options, but fantastic soup.
This restaurant is inside the botanical gardens (so worth a walkthrough!). There are clearly-marked GF options. I had the butternut squash salad and "mmmmm'd" my way through the meal. I also had the tomato basil bisque soup, which was the second best I've ever had. I love their sustainable choices in compostable cups and locally-sourced ingredients. Classy ambience too. Highly recommended!
Soups and salad dressings made in house and are gluten free. Salads are gluten free. Great food, a part of Missouri Botanic Gardens.