In a medium saucepan, combine the Thai tea mix, whole milk, and ½ cup of heavy whipping cream. Heat on medium-low until steaming, about 5-7 minutes.

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

In a separate bowl, whisk together the strained tea liquid with sweetened condensed milk and vanilla extract until smooth, about 2-3 minutes.

In a chilled mixing bowl, whip the remaining heavy whipping cream until stiff peaks form, about 3-5 minutes.

Fold the whipped cream into the tea mixture in 2-3 batches, gently combining them.

Transfer the mixture into a loaf or cake pan, cover tightly with plastic wrap, and freeze for at least 8 hours.

Once frozen, let it sit at room temperature for 10-15 minutes before scooping. Serve with optional toasted coconut flakes.