In your blender, combine ice cream, milk, and dulce de leche. Blend until well-mixed and creamy.
Drizzle dulce de leche around the inside of a glass if desired before pouring in the milkshake. Top with optional whipped cream and more dulce de leche. Serve and enjoy!
Notes
*Use 1/2 cup milk for a thicker shake, 3/4 for a thinner one.