For many Puerto Ricans, Christmastime is pasteles season. Come November, many of us are already thinking about how we’re going to score our pasteles, a complicated, labor-intensive holiday dish.

Made using layer upon layer of puff pastry and dollops of set custard you’d be forgiven for thinking that the pastel de nata, or Portuguese custard tart, is a pretty basic dessert. In reality, it’s a ...