Preheat oven to 3500F (1750C). Lightly grease a 9-inch round cake pan or line with parchment paper.
In a large bowl, cream together the peanut butter, softened butter, and brown sugar replacement until light and fluffy, about 2-3 minutes with an electric mixer.
Beat in the large egg and vanilla extract until well combined. Scrape down the sides of the bowl to ensure everything is incorporated.
In a separate medium bowl, whisk together the almond flour, baking powder, and salt until no lumps remain.
Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Do not overmix. Fold in the sugar-free chocolate chips.
Press the cookie dough evenly into the prepared cake pan. Bake for 18-22 minutes, or until the edges are golden brown and a toothpick inserted into the center comes out with moist crumbs.
Let the cookie cake cool completely in the pan on a wire rack for at least 30 minutes before slicing and serving.