I bought a “tortilla pan” in Spain which prevents this. It’s basically two pans with an interlock on one side. You cook the tortilla on one side, grab the other pan and lock it on, then flip it over and put the other pan on the heat to cook the other side. Foolproof and worth it when you cook as many as I do!
It's on every menu in Barcelona - yes, served cold.
A Spaniard taught me that mixing in some potato chips gives it some variety. He said he even sometimes makes it completely out of packaged chips.
It is a curious and useful book: the recipes are for the unfussy Spanish homestyle meals they served to the staff at el Bulli each night before opening. Each recipe is one that can scale way up, and the quantities are given to make each dish For 2, 6, 20, or 75 (!) people. It’s a good source of inspiration if you need to cook a dish for a crowd.
There are also detailed photo illustrations of the ingredients and of each step in the recipe.
He remains a delight to watch!
I've made dozens since last summer, and Kenji's technique in the video has been pretty much bulletproof for me.
His extra-creamy scrambled egg is also a mainstay now: https://www.youtube.com/watch?v=uX-Y513ohbc --- I love how little patience he has with macho restaurant culture, and that he won't even link to Gordon Ramsay, who popularized the dish.