In a medium bowl, combine the heavy whipping cream, sweetened condensed milk, vanilla extract, and ground cinnamon (if using). Whisk together until well blended and slightly thickened.
In a separate bowl, gently toss the sliced strawberries with a tablespoon of sweetened condensed milk to coat them lightly.
In serving bowls or cups, layer the strawberries and the cream mixture. Start with a layer of strawberries, followed by a layer of the cream mixture, and repeat until all ingredients are used, finishing with the cream on top.
Chill in the refrigerator for at least 30 minutes to allow the flavors to meld.
Before serving, garnish with fresh mint leaves if desired.