1. Using a small bowl, bloom 4 tbsp of unflavored gelatin by sprinkling it over 1 cup of cold water. Let it sit undisturbed for 5 minutes to soften.
2. In a medium-sized saucepan, pour 4 cups of milk and heat over medium-high heat. Bring the milk to a boil, stirring occasionally with a wooden spoon to prevent scorching.
3. Once the milk reaches a boil, add the broken cinnamon sticks. Reduce the heat to low and simmer for 4 minutes, stirring gently with the wooden spoon.
4. Remove the saucepan from the heat. Using a slotted spoon, carefully remove and discard the cinnamon sticks.
5. Add the bloomed gelatin to the warm milk in the saucepan. Stir continuously with a whisk until the gelatin is fully dissolved.
6. Pour in 28 oz of condensed milk, 1 1/2 cups of heavy cream, and 2 tsp of vanilla extract into the saucepan. Whisk thoroughly until the mixture is smooth and well combined.
7. Place a fine-mesh strainer over a large bowl with a spout. Pour the mixture through the strainer to remove any lumps or impurities.
8. Let the mixture cool at room temperature for 10-15 minutes, stirring occasionally with a silicone spatula to prevent a skin from forming.
9. Carefully pour the mixture into a silicone mold or glass baking dish. Use the silicone spatula to scrape any remaining mixture from the bowl.
10. Cover the mold or dish with plastic wrap, ensuring it touches the surface of the mixture to prevent condensation. Refrigerate for 4-5 hours or until fully set.
11. Once set, run a thin sharp knife along the edges of the mold or dish to loosen the jello. Place a serving plate upside down over the mold and invert it to release the jello.
12. Garnish the jello with fresh berries arranged neatly on top using clean hands or a pair of kitchen tongs.