We hit "Must Be Heaven" on the advice from a local and liked it very much. You go through a service line to order, and then take your food to a table or booth. There is an ice cream parlor on one side and lunch on the other.
We had a light lunch (pictured) and a sausage and kraut. Brenham has a German heritage so it seemed like the thing to try.
The place was crowded with tourists and a few locals, and we got lunch for about $20. So, if you find yourself in Brenham it might be worth a peek. I wouldn't make a special trip just to see this restaurant, but if you are going to the Blue Bell Ice Creamery (worth the trip), this is a good place for lunch.