The most popular way to serve guava in Indonesia is to make a juice with ice and sugar. But I actually rather like the idea of turning it into a smoothie by adding plain yoghurt, milk, and honey and taking out the ice and sugar, thus making it healthier and fit for a quick breakfast.
Smoothie Jambu Merah - Guava Yoghurt Smoothie
Guava is a fruit that to me resembles a pear, with thick skin ranging from green to yellow. The riper the fruit, the yellower the skin, kind of like banana in a sense. If the skin is still greenish, just wait for a couple of days until it turns more yellow before using to get a much sweeter flesh.