Preheat your oven to 350°F (175°C). Line an 8×8-inch pan with parchment for easy removal.
In a heatproof bowl, melt the butter and chopped chocolate together until smooth and glossy. A quick 20–30 second impulse in the microwave, stirring in between, works well. Let cool slightly so you don’t cook the eggs in the next step.
Stir in the granulated sugar until the mixture looks glossy and thick. The warmth from the chocolate helps melt the sugar and create a silky batter.
Beat in the eggs one at a time, then add vanilla. Mix until just combined and everything looks smooth.
Sift the cocoa powder, flour, and salt together, then fold into the batter until combined but not overmixed. A few streaks of flour are fine; we want fudgy, not tough.
Spread about half the batter into the prepared pan. Drizzle caramel sauce in ribbons over the batter. Add the remaining batter on top and use a knife or skewer to swirl the caramel into the batter for a marbled look.
Sprinkle the chopped nuts over the top if you’re using them. A light dusting of flaky sea salt on top right before baking adds a playful contrast to the sweetness.
Bake for 25–30 minutes. The edges should look set, while the center will be fudgy. A toothpick inserted should have a few moist crumbs clinging to it.
Cool completely in the pan before lifting out and slicing into squares. The caramel needs a moment to settle, which makes clean cuts easier.
If desired, rewarm a drizzle of caramel over the top just before serving for extra gloss and oomph.
Notes
Caramel Crunch Brownies are fudgy, deep-chocolate bars swirled with ribbons of caramel and finished with a crackly top and optional crunchy mix-ins for added texture.
