Open on Sunday in St. Louis
There are dozens of places open on Sundays. I would suggest you go the the Sauce website www.saucecafe.com and use their "Find a Restaurant" guide which has as one of its options under "features and attributes," "open Sundays." If you want more help from this board give us an idea of what kind of cuisine you are seeking. Generally, the restaurants on The Hill are closed Sundays and many Asian food restaurants are open, but that information only scratches the surface.
Everest, on Manchester between Sarah and Boyle in the city, is open, and features its lunchtime buffet on Sundays at $8.95/pp. I think it is a tremendous value, the Nepalese and Korean specialties are fresh, delicious, and healthy. Many vegetarian selections. Warm naan, excellent veggie pakoras. We have been going early Sunday afternoons: I think the buffet is open until 2:00.
The restaurant also offers its regular dinner menu in the evenings.
Everest Cafe & Bar
4145 Manchester Ave, Saint Louis, MO 63110
There are a lot of places open on Sundays, it depends on what you consider good. Pat's is good. Most of the CWE restaurants are open Sundays. Cafe Ventana is great for lite bites and nice patio. I'll say again. Babalu's in Kirkwood is a greatplace for a casual breakfast or lunch. Cafe Osage is another breakfast/lunch spot.