1. Add sweetened condensed milk, cream, salt, and vanilla to the bowl of an electric mixer.
2. Beat the cream on high speed until stiff peaks form, about 3 minutes. Remove bowl from mixer and gently fold in chocolate chips.
3. Pour into a loaf pan. Cover and freeze for at least 6 hours.
For the Chocolate Sauce
1. Whisk together sugar, cocoa, and cornstarch in a medium saucepan. Add water. Bring to a boil over medium-high heat. Let come to a bubble.
2. Whisk in butter, vanilla, and sea salt.
3. Let cool and transfer to a container.