70’s gas station – hot “fast” food sandwiches!!??

Back in the 70's, my Dad owned a gas station.
I remember my Mom taking us there to visit my Dad and the big treat was "hot food sandwiches" made in some magical oven!
Some vendor (like Schwan's/Stewarts?? perhaps???? [memory poor]) supplied these "ovens" - maybe like toaster ovens? - and the frozen foods/ sandwiches - and you could "cook" them right there! I remember as a kid, these were awesome! Probably the "novelty" of it - more so than it was really good.
Does anyone remember this...

70's gas station - hot "fast" food sandwiches!!??