masa harina

Time to broaden my flat baking horizon.  I just came back with a 4-lbs bag of Masa Harina, and gave up after 4 stores looking for tortilla/taco shell salad pans.  Any ideas how to get by with ordinary household containers baking the tortilla into something similar to a taco salad shell ? A friend uses an upside down muffin pan and puts the soft tortilla in between four muffin forms but I want something with a bit bigger bottom to hold the hamburger and lettuce.

Thanks much,

anna