Combine egg yolks and granulated sugar in a small bowl. Whisk until a smooth, yellow consistency forms (~30 seconds).
Next, heat heavy cream and whole milk in a sauce pan until smokes begins coming off the liquid. Turn off the heat.
Add 1/4 cup of the hot cream to the eggs and whisk until it turns a smooth and uniform yellow color. The goal of this step is to raise the temperature of the eggs, so they don’t completely cook in the hot cream. Pour the eggs into the pan with hot cream.
Turn the heat back on and heat the cream until it reaches 170 degrees F. A good way to test if it’s done is to coat the back of a spoon with the cream and pull your finger through the cream. A done cream should have a thick, smooth trail that doesn’t break. Take the cream off the heat.
Pour the cream through a fine mesh sieve into a large bowl. This will get rid of any egg or milk solids in the cream.
Add the durian flesh and use an immersion blender to incorporate it into the cream. You can also use a regular blender for this step.
Cool the cream down to room temperature and then put it in the fridge to cool completely. The cream should be in the fridge for about 20-30 minutes.
Pour the cream into an ice cream maker and churn for 15-20 minutes. The resulting ice cream should be slightly harder than soft serve.
Spoon the ice cream into a freezer safe container and freeze overnight.