Start by peeling the butternut squash then cut it into cubes, transfer these cubes to a saucepan, add enough water to cover them and let them cook for 15 minutes.
Drain all the water and add the condensed milk, the cinnamon powder and beat with a hand blender until the squash has fully dissolved.
Add the milk, the cornstarch and mix until fully dissolved. Turn the heat to medium-low and keep stirring until thickened.
When that happens, transfer this mixture to a nice baking dish, spread well and top it all with the crushed walnuts.
Take it to the fridge and let it chill for at least 5 hours.
After this indicated time, finish by adding honey to taste.
Serve.