Preheat the oven to 325°F. Lightly grease a 9x9 inch baking pan and line it with parchment paper, leaving some overhang on two sides to help lift the brownies out after baking.

In a medium bowl whisk together the flour and baking powder until well combined, then whisk in the unsweetened cocoa powder until the mixture looks even and lump free.

In a large mixing bowl stir the Splenda into the warm melted butter until the mixture looks glossy and the sweetener is mostly dissolved with no sandy layer at the bottom of the bowl.

Add the eggs to the butter mixture one at a time, whisking just until each egg is fully incorporated before adding the next, then stir in the vanilla bean paste until the batter looks thick and smooth.

Add the dry ingredients to the wet ingredients and fold gently with a spatula, scraping the bottom and sides of the bowl, just until no dry streaks of flour or cocoa remain and the batter is evenly combined.

Fold in the sugar free chocolate chips until they are evenly distributed. The batter will be thick but spreadable.

Scrape the batter into the prepared pan and spread it into an even layer, smoothing the top so it bakes uniformly from edge to center.

Bake for 25 minutes, or until the top looks set, matte, and slightly puffed with a thin crackly surface and a toothpick inserted near 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 for 45 to 60 minutes so they firm up and slice cleanly.

Use the parchment overhang to lift the cooled brownies out of the pan, place on a cutting board, and cut into 24 squares with a sharp knife.