In a large bowl, mix the manioc starch, cornmeal, and salt.
Add the softened butter and work it into the dry mixture with your hands until a crumbly, sandy mixture is formed.
Add the grated cheese and mix.
Gradually add the milk, just enough so that the mixture can be formed into flatbreads. The mixture should remain lumpy and not too wet, just moist.
Heat a non-stick skillet (Comal) over medium heat. You do not need to add fat if the skillet is good quality (the fat is already in the dough).
Take about 1/2 cup of the mixture and spread it evenly on the skillet, pressing gently to form a round flatbread (about 10-15 cm in diameter).
Cook for 3-5 minutes on one side until the edges are golden brown and the flatbread can be easily flipped.
Flip and cook for another 2-4 minutes until golden brown and fully cooked. Repeat with the remaining mixture.
Mbejú should be crispy on the outside and soft on the inside. Serve warm, ideally with a cup of hot coffee, Mate tea, or as a side to eggs or meat.