The last time we spoke with Matt Goulding, co-founder of Roads & Kingdoms, it was to hear about his book, “Rice, Noodle, Fish,” and a revelatory trip to Japan. Goulding’s most recent effort, “Grape, Olive, Pig,” focuses on Spanish cuisine. “Spain’s greatest virtue lies in that time-tested Mediterranean formula,” Goulding writes, “[of] beautiful local ingredients, impeccable technique and a ravenous appetite for all manners of flora and fauna.”