Preheat oven to 350°F (175°C). Grease and flour an 8x8 inch baking pan, or line with parchment paper.

In a large bowl, whisk together the melted butter, granulated sugar, and brown sugar until well combined.

Beat in the eggs one at a time, then stir in the vanilla extract.

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

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.

Fold in the chocolate chips, if using.

Spread the batter evenly into the prepared baking pan.

Bake for 25-30 minutes, or until a toothpick inserted into the center comes out with moist crumbs.

Let the brownies cool completely in the pan on a wire rack.

In a medium saucepan, melt the butter over medium heat. Add the granulated sugar and light brown sugar and 0.5 cup of the heavy cream. Whisk continuously until the mixture comes to a boil, about 6-8 minutes.

Reduce heat to medium-low and continue whisking. Boil for about 3 more minutes until the temperature on a candy thermometer reaches 220°F (104°C).

Stir in the remaining 0.25 cup of heavy cream until blended. Cook on medium-low for an additional two minutes.

Remove from heat. Pour the caramel sauce into a heatproof jar and let it cool at room temperature. The sauce will thicken as it cools.

Once the brownies have cooled, cut them into squares.

Drizzle the cooled caramel sauce generously over the brownies.

Serve immediately and enjoy!