Preheat oven to 180°C, and line a baking sheet with parchment paper.

In a medium bowl, whisk together flour, cocoa powder, and baking powder. In a separate bowl, use a hand mixer to beat egg and Splenda Granulated until light and fluffy. Add vanilla extract and mix until combined. Add in flour mixture, stirring until fully incorporated. Fold in half the dark chocolate.

Transfer cookie dough to the prepared baking sheet, and using lightly oiled hands, shape into a long rectangle, 6 cm wide and 2cm high. Bake at 180°F for 30 to 33 minutes, until the surface is very dry to the touch. Cool on baking sheet for 10 minutes, exactly.

Transfer cooled cookie slab to a cutting board and using a sharp serrated knife, cut the rectangle into 1,5 cm-thick strips. Place cookies back onto the baking sheet, cut-side-up. Bake at 180°F, flipping halfway through, for 10 to 12 minutes. Cool completely on the baking sheet.

While cookies bake, melt white chocolate and transfer to a skinny drinking glass or container. When cookies have cooled completely dip each cookie 3/4’s into white chocolate. Set cookies back on the baking sheet and chill until chocolate hardens. Meanwhile, melt the remaining dark chocolate and transfer to a small zip-top bag. Snip off the corner and decorate chilled cookies with eyes and mouths to resemble ghosts.