Heat milk, cream and heavy cream in a pot over medium-high heat just until steaming.

Remove from heat and whisk in 1 2/3 cup dulce de leche (600 gr) until completely smooth.

Whisk in the vanilla and the scrapings of a vanilla bean.

Allow to cool.

Transfer the mixture in a suitable container and place it in the freezer. Freeze 4-5 hours until firm, stirring with a fork every 45 minutes.

After 2 hours remove ice cream from freezer. Swirl in the leftover dulce de leche with a table knife. Do not over stir to maintain the marbled effect.