- Place cubed squash, salt, and sugar in a heavy saucepan. Add water to barely cover squash and bring to a boil over high heat.
- Lower the heat to medium and simmer until the squash is tender but still firm, about 5 minutes. Transfer pan to the sink and run cold water into it in a thin stream for about 6 minutes to slowly stop the cooking process and cool the squash completely. Drain the squash batons briefly so they still retain a bit of water and return them to the saucepan.
- Over high heat, stir in the butter until it melts completely, then lower the heat to medium. The idea is to create an emulsion by letting the butter thicken the remaining sugary water and coat the squash; stop cooking as soon as this happens so coating does not separate.
- Add more salt if you wish and keep the squash warm over very low heat.