In a medium saucepan, whisk together ½ cup of heavy whipping cream, 1 teaspoon of ground cinnamon, ½ teaspoon of allspice, and ½ cup of pure pumpkin puree. Heat over medium-low heat until warm, approximately 3-5 minutes, stirring consistently.

Reduce heat to low and simmer for 15-20 minutes, stirring occasionally until the mixture thickens slightly and becomes aromatic.

Remove from heat and allow the mixture to cool completely at room temperature for about 10-15 minutes.

Whisk in another 1 cup of heavy whipping cream and ½ cup of sweetened condensed milk until fully combined.

Pour into a clean mason jar or airtight container, seal well, and refrigerate for at least 2 hours before using. Shake well before each use.