In the countryside of Central Java, not far from the dramatic marvel of the ninth-century temple of Borobudur, is the most surprising restaurant. Jejamuran has separate channels for entrance and exit with an airport-style check-in service. Inside, great halls of people are served nothing but mushrooms. Dishes from across Indonesia, from rendang to sate, are rendered beautifully in fungi. Our highlight was the richly spiced tongseng curry, which is more usually made with goat meat.