Foaming at the mouth, Part II: el Bulli's tortilla de patatas Marc Singla foam
For the longest time, I was convinced that only the French know how to make a good omelette. Rachel and I had eaten our share of Spanish tortillas and Italian frittatas, and found them wanting: thick rounds of leaden, overcooked eggs with a consistency more reminiscent of a custard forgotten in the oven than an old world culinary classic. The French insist an omelette should be thin, light, and cooked just long enough to firm one side while leaving the other creamy.
The French are right.
Then we visited Cal Pep, one of Barcelona's most famous tapas joints, and discovered a tortilla that puts omelettes to shame. There, cooks scoop a mixture of potato, chorizo, onion and golden, creamy eggs into sizzling hot, high-sided small pans. One flip and a minute or two later, they slide a thick, lightly caramelized disc about the size of a large hamburger patty onto a plate, slather the top with allioli, a garlicky mayonnaise better known by its French name, aïoli, and await the delighted squeals of ravenous customers.
What makes this tortilla so special is that, unlike its Iberian and Italian cousins, it offers that magical mix of cooked and creamy egg that makes a French omelette superior. Cut open Cal Pep's tortilla, and, underneath the lightly caramelized crust, lies a core of warm, not-quite-set egg. Allioli complements the unctuousness of the interior while nuggets of spicy chorizo and potato add body and flavour. It's enough to make me forget France forever.
The tortilla's iconic stature in Spanish gastronomy means that Ferran Adria can't resist riffing on it, even if he's got to crib from another chef to do it. El Bulli's evolution of the hot 'tortilla de patatas Marc Singla' foam from el Bulli: 1998-2002 deliciously deconstructs the standard dish. Raw yolks and a barely cooked sabayon mean the egg portion of this tortilla is a golden syrup that flows on the palate, and Adria opts for a tangle of caramelized onions for their complex savoury-sweet bite.
Yet it's the potatoes that grab your attention. Gone are the chunks of spud, replaced instead by an almost overwhelmingly rich foam made by boiling potatoes, enriching them with cream and olive oil, then blending and pouring the mixture into an iSi Gourmet Whip charged with nitrous oxide. The Gourmet Whip is unique because it can be heated, so after spooning caramelized onion into the bottom of a martini glass and gilding it with some raw egg yolk and sabayon, the dish is crowned by a layer of piping hot potato.
Despite my misgivings -- blending potatoes is normally a recipe for glue, not haute cuisine -- the foam is spectacular. It has a noticeably buttery taste even though it has no butter, and the texture is, not unexpectedly, light but still substantive enough to form the backbone of the dish. My only complaint, and here, yes, I'm trying to have it both ways, is that I miss some of the complexity of flavour and texture that comes from the caramelized exterior of Cal Pep's tortilla.
I've tried to reproduce Cal Pep's tortilla at home, but I'm not quite there yet. Problem number one is that my non-existent Catalan makes translating the recipe difficult (someone help me, please). Problem number two is that I have yet to find a pan suitable for the job. My results so far have been good but not stellar: a respectable crust, but a slightly overcooked centre. No matter, I can always turn to el Bulli's version, or, failing that, Rachel assures me I prepare a mean French omelette.