First mix salt, sugar and cornstarch in a saucepan, then add the milk, bring to the boil, stirring constantly and allowing it to thicken, then remove from the heat, add the butter until it melts completely and leave to rest for 30 minutes in a bowl, covered. from film in contact to prevent it from oxidising.
Pour the now almost cold mixture into the bowl of the mixer, add the flour and the chopped yeast and knead until you obtain a smooth and elastic dough.
Divide the dough in half, place one half in a bowl and cover to let it rise; instead divide the other piece of dough in half again.
Mix 15 g of cocoa with 2 tablespoons of water and incorporate them into one of the 2 remaining parts of the dough, working briefly.
Mix the remaining 5 g of cocoa with the remaining spoonful of milk and incorporate it into the last piece of dough.
You will have obtained a lighter and a darker dough, place them in separate bowls, cover and let the 3 doughs rise for at least 2-3 hours or until doubled in size.
Take the 3 doughs and, one at a time, deflate them with your hands and divide them into 7 equal parts: in the photo you only see 2, but you have to do it with all 3, obtaining a total of 21 balls of dough.
Start with a light brown ball of dough and roll it on the work surface to shape it until you obtain a cord almost as long as the mold.
Take a ball of dark brown dough and roll it out into a very long rectangle, place the light brown roll on top and roll the rectangle around it, closing it.
Now take a ball of white dough, roll it out into a long rectangle and wrap it around the other two.
Proceed in the same way with all the other balls, obtaining 7 different rolls, white on the outside.
Place all the rolls inside the mold lined with baking paper and leave to rise again for at least 2 hours or until doubled, then brush with milk and cook for about 40 minutes in a fan oven preheated to 170°C.
The leopard bread is ready, let it cool completely before cutting it into slices and enjoying it.