In a 2-quart microwave-safe bowl, microwave the sweetened condensed milk and chocolate chips on high for 1 minute.
Let sit for 1 minute and stir. If chips are not all melted, microwave another 30 seconds.
Add vanilla and pour into a buttered 8-inch square pan, lined with aluminium foil.
In a separate bowl, microwave the dulce de leche just until pourable: 0 - 20 seconds. Pour over chocolate fudge.
Use a cold butter knife to swirl the caramel. Sprinkle with sea salt.
Cool completely. Cut into 1-inch squares and enjoy!
Be aware that a package of dark chocolate chips may not contain 2 cups. Measure before starting the recipe.
Next time I make this, I will add some toasted pecans to the top since it's reminiscent of turtle candies!