That was a little confusing, given that the gaucho food of Argentine steak places has more the connection to pao de queijo (from the part of So. Brazil that shares the Pampas and gaucho culture), which literally means 'cheese bread' and is, indeed, bread.
As Antonius said, you probably were served the ubiquitous arepa con queso at La Tablas.
If you enjoyed that, you might also try Salvadoran pupusas de queso, or Equadoran/Peruvian torta de choclo con queso, which you will find is more like the corn pudding of Urugay and less like the arepas of Colombia and Venezuela.
Towards the sweetest end of the spectrum of such things is quesadilla Guatemalteca, which is a damn fine dessert and has nothing to do w/ Mexican quesadillas except for cheese.
Not surprisingly, my grocery leads remain largely the same. La Unica has everything you will need, from mixes, to frozen, ready to heat, to fresh from the kitchen arepas.
Any of the Colombian. Venezuelan, Salvadoran, Peruvian, or Ecuadoran establishments discussed herein should have their version of the staple corn cake.