I was recently in South East Asia and my most memorable meal was on the 3rd class train from Bangkok to the border of Cambodia.

In the morning a woman came through selling sweet sausage and egg on top of rice and there was a package of savory liquid to put on the rice.

Does anyone know what this liquid was? I had also seen it put on rice later in the journey but I don't think it was fish sauce.

I'd love any suggestions as I'm hoping to make this at home.