While I was in Coba, I was able to pick up a few Seville oranges. I'd have liked to bring more back, but I'm hoping to go to Abastos soon and get a lot to freeze because I LOVE them. There is nothing quite like them. Maybe someone I can live in Merida for a while and cook with them every day.
There are lots of great recipes that use bitter oranges, but I turned the ones I bought into cebollas curtidas.
Juice of three narajanas agrias
1/2 kilo red onions, sliced
1/2 tsp salt, or to taste
Other spices, if desired, like a bit of allspice, black pepper, and/or cloves
Cover the red onions with boiling water and let them sit for 1 minute, then drain. Combine with the juice, salt, and spices and let sit for an hour. They'll just get better and better the longer they sit and will last quite a while in the fridge. I can't imagine them last more than a day, though.
These go on lots of different things. I put them on mole here at home, but they should be on tacos, salbutes, panuchos, pibils, and various other meat dishes. Or anything else you like. They are amazing.