Ingredients:

  • 1 cup (225g) unsalted butter, melted and slightly cooled
  • 1 cup (200g) dark brown sugar, firmly packed
  • 1/2 cup (100g) granulated white sugar
  • 1 large egg, room temperature
  • 1 large egg yolk, room temperature
  • 2 tsp pure vanilla extract
  • 2 1/4 cups (280g) all-purpose flour
  • 1 tsp baking soda
  • 1/2 tsp sea salt
  • 1 1/2 cups (250g) semi-sweet chocolate chunks or chips
  • 1/2 cup (120ml) salted caramel sauce
  • 1 pinch flaky sea salt

Instructions:

  1. Preheat the oven to 350°F (180°C) and ensure a 10-inch or 12-inch cast iron skillet is ready.
  2. In a large mixing bowl, whisk together the melted butter, dark brown sugar, and granulated sugar for approximately 2 minutes until the mixture appears glossy and the sugars begin to dissolve.
  3. Add the whole egg, egg yolk, and vanilla extract. Whisk vigorously until the mixture is pale and thickened.
  4. Sift the flour, baking soda, and salt directly into the wet ingredients. Use a rubber spatula to fold the dough until just combined, being careful not to overmix.
  5. Fold in the semi-sweet chocolate chunks or chips. Transfer the dough into the cast iron skillet and spread it into an even layer.
  6. Dollop the salted caramel sauce over the top of the dough and use a knife or skewer to marble it into the base. Sprinkle with a pinch of flaky sea salt.
  7. Bake for 25 minutes. The edges should be golden brown and set, while the center should still have a slight wobble. Remove from the oven and let rest for 10 minutes to allow carry-over heat to finish the center while maintaining a gooey texture.