Mix the cassava flour, salt and baking powder together in a large bowl. Heat the milk, water and butter or oil until the milk just begins to boil. Stir the hot liquid into the flour mixture with a spoon or with the dough hook of an electric mixer. Keep stirring until all the flour is incorporated and the mixture is warm but not hot. Touch the dough with the back of your fingers—they should feel comfortably warm against the dough.
Beat the egg in a separate bowl then mix it into the dough. Keep blending until the dough is elastic and smooth, then fold in the shredded cheese. Cover the dough and chill—it should be colder than room temp before baking but can rest in the fridge up to 24 hours. Heat the oven to 375°F . Drop spoonfuls of dough about as big as a golf ball onto a lightly greased cookie sheet or spoon the dough into muffin tins, traditional size or mini. Bake until the tops are golden and a roll sounds hollow when you tap the bottom, about 20 minutes depending on size. Serve immediately. Baked rolls will hold up to a day, but reheat in the toaster oven before serving.