In a medium bowl whisk eggs until foam begins to form (you may want to use a stand mixer, my arms started to hurt lol)
In a saucepan over medium heat combine milk, heavy cream, and sugar and stir until mixture is well combined with sugar all melted.
Gradually add milk mixture to egg mixture, whisking continuously
Pour the mixture through a sieve into a small bowl or large measuring cup.
Divide the mixture into your ramekins filling up about 2/3 up and prepare your water bath by placing your ramekins into a large roasting pan and pouring boiling water around them until the water reaches half way up.
Bake for about 45 minutes or until the tops are puffy but the middle is slightly jiggly.
Cool in the fridge for at least 2-3 hours
You can serve with caramel sauce over top or you can take purin out and place caramel sauce on the bottom of a small dessert plate, then place the purin on top.
Enjoy!