Preheat your oven to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper, leaving a 2-inch overhang on each side for easy removal after baking.

In a small saucepan, combine the bittersweet chocolate and unsalted butter. Melt over very low heat, stirring constantly until smooth. Alternatively, you can melt the mixture in the microwave at 50% power in short bursts, stirring frequently.

In a large mixing bowl, whisk together the eggs, granulated sugar, and salt. Beat until the mixture is pale and thick, about 2-3 minutes. Gradually pour in the warm melted chocolate mixture, whisking until combined.

In a separate bowl, whisk together the flour and cocoa powder, then sprinkle it over the chocolate mixture. Gently fold in the dry ingredients until just combined.

Spread the batter evenly into the prepared pan. Bake for 20-25 minutes, or until the edges are set and a toothpick inserted into the center comes out with just a few moist crumbs. Transfer the pan to a wire rack to cool completely.

In a medium bowl, combine the salted caramel sauce, peanut butter, and roasted peanuts. Stir until smooth. This mixture will be thick and creamy, forming the nougat layer of the Snickers brownies.

Once the brownies are fully cooled, spread the nougat layer evenly over the surface.

In a small microwave-safe bowl, combine the dark chocolate and coconut oil. Melt in the microwave in short bursts, stirring between each interval, until the chocolate is smooth and glossy. You can also melt the chocolate on the stovetop using a small saucepan over low heat.

Pour the melted chocolate mixture over the nougat layer, spreading it evenly with a spatula to fully cover the peanut butter caramel.

Refrigerate the brownies for about 30 minutes to allow the chocolate topping to set. Once the chocolate is firm, use the parchment paper overhang to lift the brownies out of the pan.

To slice, heat a knife under hot water, dry it, and then cut the brownies into squares for clean edges.