Preheat oven to 350°F. Spray an 8x8" pan with oil and line with parchment paper so that it hangs over the edges.
In a microwave safe bowl, melt the butter and chocolate chips (stir every 30 seconds until melted, ~1-2 minutes total). Let it cool slightly (so that it doesn't cook the eggs when added in the next step).
In a large bowl, beat the eggs with a whisk for about a minute. Add the sugar and continue to whisk for another 2-3 minutes until it's slightly thick, light, and airy. Then, slowly pour in the warm butter/chocolate mixture and whisk for another minute.
In a small bowl, combine the flour, cocoa powder, and salt. Then, gently fold them into the wet ingredients just until all flour streaks are gone. The batter will be slightly thick.
In a medium bowl, mix the coconut, sweetened condensed milk, and powdered sugar together with a spatula until well combined.
Scoop half of the brownie batter into the prepared pan and spread it around with a spatula so that it's even across the bottom.
Add the chocolate caramel squares on top of the brownie batter in an even layer.
Carefully spread the coconut filling over the chocolate caramel squares.
Finally, spread the remaining brownie batter on top of the coconut filling, covering it completely and evenly.
Bake for 30-40 minutes or until the edges begin to harden and a smooth film sets across the middle. The batter should leave behind a streak on a toothpick inserted into the middle.
Let the brownies cool in the pan until they're sturdy enough to be lifted out. Cool completely for clean cuts, or indulge while they're warm and gooey!
Store in an airtight container at room temperature for up to 1 week.