In a saucepan, mix the coconut milk and water.
Add the sugar, salt, turmeric, and fish sauce; stir we'll to combine.
Add ginger, onion, and squash and bring to a low boil.
Stir gently and reduce heat to simmer.
Cook about 20-25 min., stirring occasionally. Check if squash is tender and cook a few or minutes or as needed (add more water if getting dry).
Remove from heat, remove ginger, and let sit a few minutes to thicken sauce. Garnish with cilantro and serve with warm white or brown rice.