This Laurel location is the last surviving Tastee-Freez in Delaware. It was built as a walk-up in the 1950s. This roof and dining room were added in the 1970s. [photo thanks Glenn Van Fleet]

There was a Big T Tastee-Freez in Laurel, MD which is gone now. That location was built around an old McDonald's building (note the sides of the buildings). For more, see these websites: 1, 2, and 3. The examples shown here have two or three vertical grooves in the roof. The Laurel, MD location had five grooves. I believe all of the locations built in this style were called "Big T"s. If you come across any more examples of these buildings, I'd love to know about them.