Instructions:
- Phase 1 (Caramel): Melt sugar slowly in a dry saucepan until it achieves a deep amber colour. Whisk in the cubed butter until fully incorporated and bubbling. Slowly pour in the warmed heavy cream while whisking constantly. Remove from heat, stir in 1/2 tsp sea salt. Cool completely until thick and pliable.
- Phase 2 (Dough): Whisk together flour, baking soda, and fine sea salt in a medium bowl. Set aside.
- Cream the softened butter, brown sugar, and granulated sugar in a mixer until light and fluffy (about 3 minutes). Scrape down the sides.
- Beat in eggs one at a time, ensuring each is incorporated before adding the next. Mix in the vanilla extract.
- Gradually add the dry mixture to the wet mixture on low speed until just combined. Fold in the bittersweet and milk chocolate chunks using a spatula.
- Phase 3 (Assembly): Scoop dough (about 2 tablespoons per cookie) onto a parchment-lined baking sheet. Gently press one chilled caramel dollop into the centre of each dough mound. Partially fold dough over the caramel to conceal it.
- Chill the formed cookie dough balls for a minimum of 1 hour.
- Preheat oven to 375°F (190°C). Bake for 10–13 minutes. Cookies should look slightly underbaked in the centre with golden-brown edges.
- Immediately upon removal from the oven, lightly sprinkle the tops of the cookies with flaky sea salt. Let cool on the sheet for 5 minutes before transferring to a wire rack.