Preheat oven to 375ºF. Add bacon brown sugar to a large Ziploc bag and toss until bacon is coated.

Line a baking sheet with a wire rack and lay bacon on the rack. Put the baking sheet on the top rack of the oven and bake until crisp, about 15 minutes. Remove from the oven. Let cool, and then chop into large chunks.

Preheat the oven to 350ºF. Butter the sides and bottom of a 9×13-inch baking pan. Line the pan with parchment paper and grease.

In a medium bowl, whisk the flour, salt, and cocoa powder together.

Put the chocolate and butter in a large microwavable bowl and microwave in 30 second increments, stirring each 30 seconds, until the chocolate and butter are completely melted and smooth. Add the sugars. Whisk until completely combined. The mixture should be room temperature.

Add 3 eggs to the chocolate mixture and whisk until combined. Add the remaining eggs and whisk until combined. Add the vanilla and stir in.

Sprinkle the flour mixture over the chocolate mixture. Using a rubber spatula (not a whisk), fold the flour mixture into the chocolate until just a bit of the flour mixture is visible.

Pour half the batter into the prepared pan and smooth out into an even layer. Drizzle half of the caramel sauce or dulce de leche around the brownie batter. Sprinkle half of the bacon bits evenly over the batter. Spread the remaining batter on top, and repeat with remaining caramel and bacon.

Bake in the center of the oven for 30 minutes, rotating the pan halfway through the baking time, until a toothpick inserted into the center of the brownies comes out with a few moist crumbs sticking to it. Let the brownies cool completely, then lift them out of the pan using the parchment paper. Cut into squares and serve.

Store at room temperature in an airtight container or wrap with plastic wrap for up to 3 days.