In a small pan over low heat, combine caramels, milk, and salt, stirring constantly until smooth. Set aside and let cool.
Preheat oven to 400 degrees F.
In a microwave-safe bowl combine chocolate chips and butter. Microwave for 2 minutes and whisk until smooth.
Whisk in powdered sugar until combined.
Add 3 eggs and 1 egg yolk, and whisk until combined.
Add vanilla and flour and mix again.
Generously spray four 1 cup oven-safe cups with cooking spray, and evenly fill with batter.
Spoon a generous amount of caramel into each cup (reserve the rest of the caramel for serving).
Bake on a cookie sheet in the oven for 13-15 minutes until the outer edges are set and the center is still soft.
Remove from oven and let cool for 2-3 minutes before inverting onto a plate drizzled with caramel sauce.
Notes
Whether you’re using pyrex or ramekins, we’d still recommend cooking them on a cookie sheet. Just in case anything overflows, it will save you a lot of clean-up in the long run.