Thengai Sadam is a typical South Indian mixed rice variety made with freshly grated coconut. This is an easy recipe to follow.
We have always used Sona Masuri or Poni Arisi for making this rice. Basmati Rice is not used for making this mixed rice variety.
Cooking the rice with 1:2 ratio should give you the perfect texture as rice grains has to be separate and not mushy.