Pour water into large pot until halfway full. Add salt and sugar (if using).
Bring water to a boil.
Add milk and unsalted butter. Slowly add corn. Add more water if necessary to cover corn. Reduce heat to medium.
Boil for 3 minutes (or longer if preferred). Please note corn kernels will become "very tough" if boiled longer than 10 minutes.
Drain before serving.
Remove husks and silks from each ear of corn. Cut in half (optional). Before boiling, "wash" corn in clean sink filled with warm water and 1/2 cup of salt. Rinse in clear/warm water. I always do this to remove insects.
Yellow corn is already sweet. However, if you prefer more sweetness, add 1/2 teaspoon of granulated sugar to the water mixture before boiling corn.