Method
1. Add milk and heavy cream to a clean saucepan
2. Heat until bubbles form and turn off heat - medium heat
3. Add egg yolk and sugar to a clean medium bowl
4. Whisk until pale and light - approx 2 min
5. Transfer milk mixture to the egg mixture gradually
6. Transfer back to the saucepan and heat until thickened while stirring occasionally - medium heat
7. Remove mixture then set aside
8. Prepare a clean baking dish with ice water
9. Submerge the stainless steel bowl in baking dish
10. Strain custard into the bowl inside the ice bath
11. Stir until completely cool
12. Add kefir cultured milk to the stainless steel bowl
13. Churn in ice cream maker
14. Freeze until firm - 1 hr