Pour the milk and cream into a medium size saucepan and bring to a boil over medium heat, reduce to a simmer and simmer for about 5 minutes. Then remove from heat and whisk in most of the dulce de leche until dissolved (save some to pour in later).
Whisk in vanilla extract and transfer to a metal bowl. Chill the mixture by putting the metal bowl in a larger bowl of ice water for about 15 minutes.
Pour the cold mixture into the frozen bowl of the ice cream maker. Churn for about 15 to 20 minutes until creamy and frozen.
Transfer ice cream to a freezer safe container. Swirl remaining dulce de leche into the ice cream mixture. I spooned it in and swirled it around with a butter knife. Cover and place in freezer. Allow to freeze about 3 hours prior to serving.