Prepare the Milk and Spice Mixture: In a medium saucepan, combine 3 cups of the evaporated milk with the sweetened condensed milk, brown sugar, ground cloves, nutmeg, and cinnamon sticks. Heat the mixture over medium-low, stirring continuously until it begins to simmer. Once it reaches a gentle boil, reduce the heat to low, then remove the cinnamon sticks.

Create the Cornstarch Slurry: In a small jar or bowl, combine the remaining 1/2 cup evaporated milk with the cornstarch. Shake or whisk vigorously until the mixture is smooth and free of lumps.

Incorporate the Slurry and Coconut: Slowly whisk the cornstarch mixture into the saucepan, ensuring it blends smoothly into the milk mixture. Gently fold in the shredded coconut and continue cooking over medium-low heat, stirring frequently, until the mixture thickens to a pudding-like consistency, approximately 4-5 minutes.

Set the Natilla: Remove the thickened mixture from heat and carefully pour it into an 8"x8" square baking dish with deep sides. Allow it to cool at room temperature for at least 1 hour.

Chill and Garnish: After the initial cooling, sprinkle ground cinnamon evenly over the top of the natilla. Transfer the dish to the refrigerator and chill for an additional 1-2 hours, or until fully set. Once firm, cut into 25 squares and serve.