In a shallow bowl, combine egg and 50mL milk.
In a sauce pan, melt butter under medium-low heat.
Dip bread slices in egg mixture for 10-15 seconds. Fry slices until golden brown, then flip to cook the other side.
In a small pot, combine 100mL milk and corn starch. Boil over medium heat. Stir constantly until it starts to thicken. Remove the pot from heat immediaitely. Add 1 tbsp condensed milk to it. Mix until combine.
In a small bowl, combine ovaltine powder and kinako powder.
Put one slice of french toast on a plate. Spread a thin layer of condensed milk on top.
Place the other slice of french toast on top. Use a spoon to press down the middle of the toast. Pour the thickened milk tohe "hole" on the toast. Sift the ovaltine+kinako powder all over the toast. Sift the cocoa powder on top.