Jasmine, a long-grain, white, aromatic rice, originates from Thailand, and on that basis alone is probably the most authentic type of rice to serve with Thai food. It is even sometimes referred to as "Thai rice." Beyond that, the soft, slightly-sticky texture and mild flavor of the rice suits Thai food very well, and it is very easy to prepare.
To prepare jasmine rice, use a 2:1 ratio of water to rice (when cooking for myself, I usually use half a cup of rice and a cup of water). Bring the rice and water to a boil, then cover and reduce heat, simmering the rice for twenty minutes. Leave covered while it cools, and that's it, it's done.
There are various variations on the basic recipe, although these are usually better as a separate side dish, and don't work well as a bed for curries, which is my usual use of jasmine rice. For the first, simply substitute chicken broth for half the water -- this will to give the rice a strong flavor. The second, coconut rice, is more involved. Here's the recipe:
1 cup Coconut milk
1 cup Water
1 cup Jasmine rice
1 tsp Ginger, chopped
1/2 tsp Salt
1/2 tsp Cilantro
Bring coconut milk, water, rice, ginger, and salt to boil in pot, cover and reduce heat, simmering for 20 minutes. Leave in pot to cool for ten minutes, then remove from pot and sprinkle with cilantro
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