In Castille it’s anything-roasted, or roasted-anything. If it was able to move by itself, it ran less than you did and it’s a holiday, you roast it. When I worked in Valladolid I had coworkers who were “vegetarian except for big holidays”; the rest of the Castillians nodded, those of us from other Spanish regions thought a bit before nodding, the foreigners needed it explained. If you try to eat a Castillian veggies-only holiday meal you’re on bread and drinks, as even the salad will have meat.
A lot of Spain celebrates Resurrection Sunday with lamb. Roast lamb, grilled lamb, barbecued lamb, lamb with Mexican sauce, lamb paella, lamb on the rack - whatever, but lamb. There’s also going to be other stuff (probably a lot of it least the host be called skimpy) but if there isn’t lamb it’s not Easter Sunday. The Lamb has risen, long live (or rather not) the butchered lamb!
For many small holidays and family celebrations, roast chicken and (specially in Madrid) fried chicken are the to-go meals; the advantage of fried chicken is, precisely, that it works better if you’re on the go, such as for a picnic. It’s been years and I’m still explaining to other Spaniards what is racist about sarcastically saying that you’re going to invite a black guy over for fried chicken*; people here understand sarcasm as being impolite, but not fried chicken as having racist connotations.
- For anybody who’s drawing a blank: Sergio López and Tiger Woods.