Add 200 ml whole milk, 200 ml heavy cream and ¼ tsp vanilla essence to a saucepan. Heat on low and mix continuously until it reaches between 60 °C (140 °F) and 70 °C (158 °F) (or until small bubbles appear around the edges of the pan). Be careful not to overheat and scold the milk. Once hot, remove the pan from the stove and set aside.
In a heat-proof mixing bowl, add 2 pasteurized egg yolk, 70 g sugar, 1 tsp cornstarch and the black sesame paste. Mix until smooth.
Add a few tablespoons of the hot milk/cream mixture to the bowl while whisking to temper the eggs.
Gradually pour the rest of the milk/cream into the bowl while whisking.
Wipe out the saucepan and pour the contents of the bowl back in.
Return the saucepan to the stove and stir continuously over a low/medium-low heat until thickened to a custard-like consistency. Scrape the bottom from time to time to prevent burning.
Pour the thickened mixture back into the heatproof bowl and place it in a bowl of ice to speed up the cooling down period. Cover the surface with a piece of plastic wrap to prevent a skin from forming on the top.
Once cool to the touch, take your container from the freezer and pour the ice cream mixture inside. Cover with plastic wrap or a lid and place it in the coldest part of your freezer.
Whisk every 30-45 minutes for 3-4 hours (6 times in total). I recommend setting a timer so you don't forget!
Switch to a spatula when it becomes to thick to whisk.Once you've finished churning, freeze for another 2-3 hours to set fully. Rest on the counter 5-10 minutes before scooping.
Enjoy!