When I look at the recipe it kind of looks familiar, all of the béchamel sauces I have looked up look kind of similar they just seem to lack rhe amount of herbs (parsley/thyme) that i remember seeping out the side of the sliders. (It wasn’t like the sauce was green it was still whit just lots of green flecks from memory)
I also misrecalled it being cooked on a cookie sheet/pan. I remember my mom individually wrapped these suckers in tin foil (maybe moreso for transport and eas of access at these gatherings). At least that is what I recall (sorry my memory is shit ) maybe they were in a pan sometimes.
The other main Issue I see with this sandwich is we never put cheese and sauce on top of the bread to make it crispy. Who knows though my mom was known for altering recipes to her liking, and we just grew up with it being the norm. Like my mom’s tuna noodle caserole was made with canned chicken instead of tuna because she hates the tastw and smell of fish .
Wouldn’t be surprised if this was some “we have croque monsieur at home” the crock monsieur at home:
All I know is… If it is… The crock monsieur at home is delicious…
That blog post you linked I don’t think is it because I don recall poppyseeds.
Thank you so much for your help! It is greatly appreciated!!