In a medium-sized saucepan, bring the cream and milk to a gentle simmer over medium heat, stirring occasionally to prevent a skin from forming on top. Once it’s barely simmering, reduce the heat to low.
2 cups heavy cream, 1 cup whole milk
While the cream mixture is heating up, vigorously whisk the yolks and sugars together in a large bowl. The yolks will thin out slightly and turn more pale in color.
6 large egg yolks, 3/4 cup granulated sugar, 1/4 cup packed light brown sugar
Once the cream reaches a gentle simmer, slowly pour or ladle it into the yolks while whisking continuously. Return the mixture to the saucepan, scraping everything from the bowl with a spatula.
Cook over low heat and stir the mixture until the liquid has thickened slightly and coats the back of a spatula or spoon, approximately 8-10 minutes. Optionally, if you want to make sure the yolks are cooked to a safe temperature, you can use a digital thermometer to check that the temperature has reached 165°F.
Remove from the heat and stir in the vanilla, then chill in the refrigerator (note: you can optionally transfer the mixture to a bowl with a spout first, which will make it easier to pour into the ice cream maker). To prevent a skin from forming on top, gently press plastic wrap directly against the surface of the mixture.
1 1/2 teaspoons pure vanilla extract
Stir in the mashed bananas, then add to an ice cream machine and prepare according to the manufacturer's instructions. In the final 5 minutes, add the chopped wafers.
2 medium ripe bananas, 1 cup roughly crushed vanilla wafers
Enjoy immediately, or transfer to a freezer-safe container with a lid or a loaf pan with plastic wrap pressed to the ice cream, and chill in the freezer until ready to serve.
Notes
Makes about 2 quarts.
If your ice cream machine is only 1.5 capacity, reduce the recipe by half to ensure it will fit in your machine.
Churning time will depend on your machine, and can be as little as 20 minutes or as much as 1 hour.