Preheat the oven to 325°F and line a 9x9-inch square baking pan with parchment paper, leaving an overhang on two sides for easy lifting. Lightly grease the parchment and exposed sides of the pan.

In a medium bowl, whisk together the flour and baking powder until well combined. Add the cocoa powder and whisk until the mixture is evenly dark with no visible streaks.

In a large mixing bowl, combine the melted butter and Splenda. Whisk until the mixture looks thick, glossy, and well blended.

Add the eggs to the butter mixture one at a time, whisking well after each addition until the batter is smooth and slightly thick.

Whisk in the vanilla bean paste until fully incorporated.

Add the dry ingredients to the wet ingredients. Using a spatula, gently fold the dry mixture into the wet mixture just until no dry flour remains; do not overmix.

Fold in the sugar free chocolate chips until they are evenly distributed throughout the batter.

Scrape the batter into the prepared pan and spread it into an even layer, smoothing the top with a spatula.

Bake for 25 minutes, or until the edges are set and a toothpick inserted in the center comes out with a few moist crumbs but no wet batter.

Place the pan on a wire rack and let the brownies cool completely in the pan. Use the parchment overhang to lift the cooled brownies out, then slice into 24 squares and serve.