Slice the bolillo rolls into slices that are about 1 inch thick.
In a large pan, add the brown sugar, cinnamon and water.
Heat the pan over a high heat until boiling, reduce the heat to medium and cook for 10-15 minutes, until a syrup has formed. Cover and keep warm but leave to the side.
Separate the egg whites, add a pinch of salt and whisk until light and fluffy.
Add the egg yolks to the fluffy egg whites and continue whisking to combine.
Heat some oil in a frying pan at a medium-high heat.
Take a slice of bread and dip it in a bowl of milk for a couple of seconds on each side, to soften the bread slightly.
Next, dip the bread in the whisked eggs until fully coated on all sides.
Add this slice of bread to the frying pan and fry until golden brown. Flip the bread so all sides are fried for 30-60 seconds.
After each side has been fried, remove the slice of bread and place it on a plate with a paper towel to absorb the excess oil.
Repeat this until all of the bread slices have been fried.
Add the fried bread to the saucepan with the syrup and allow them to soak for a few minutes.
Serve on a plate with extra syrup on the side.