Three out of four people prefer potato omelette with onion
The CIS also highlights that more than half prefer it rare.

Three out of four people believe that the Spanish omelette recipe should be made with onion, and more than half (53.3%) prefer it to be cooked "rare." On the other hand, 28.9% believe it is better "well done," compared to 15.5% who are equally inclined to leave it "medium."
This is evident from the data from the third Tourism and Gastronomy analysis published this Monday by the Center for Sociological Research (CIS), conducted in July, based on nearly 3,000 surveys, which reveal the opinion of the Spanish people regarding this controversial dispute surrounding one of the classic recipes.
However, the study highlights that for those surveyed, potato omelette is not the most representative recipe, but rather paella. In fact, four out of ten respondents think so. Trout is chosen as the second choice by 24% of those surveyed. Iberian ham completes the podium.
The CIS also takes a look at the most typical dishes of Spanish cuisine by autonomous community. In Catalonia, the undisputed winner is pan con tomate (31.2%), followed by calçots (17.7%) and escudella (15.5%). Rounding out the top five are cannelloni (9%), and, a long way behind, butifarra with beans (4.5%).