In a medium saucepan, combine Thai tea mix, whole milk, and ½ cup of heavy cream over medium-low heat. Stir gently as the mixture heats for 5–7 minutes.

Remove from heat and strain the mixture through a fine mesh sieve into a large bowl to separate the tea leaves.

In the strained liquid, mix in sweetened condensed milk and vanilla extract until smooth.

In a separate chilled bowl, whip the remaining heavy cream until stiff peaks form, about 3–5 minutes.

Gently fold the whipped cream into the tea mixture in batches, combining without deflating the whipped cream.

Transfer the mixture to a loaf pan and cover tightly with plastic wrap. Freeze for at least 8 hours.

Before serving, let it sit at room temperature for 10-15 minutes for easier scooping.