Mango sticky rice has long been a classic of Thai cooking, but the popularity of this delicious dessert made from sticky rice, coconut sauce, fresh mangoes and roasted mung beans is currently going through the roof in Thailand and beyond. It all started at a performance from successful Thai rapper Danupha Khanatheerakul, better known by her stage name Milli, at the Coachella festival in the US. The 19-year-old pop star brought a plate of mango sticky rice on stage at the April festival and took bites from it between singing in front of thousands of cheering fans. Since then, demand for Khao Ni…