Cover a 9-inch x 9-inch rectangle baking dish with parchment paper. Set aside.
In a medium-sized mixing bowl, stir peanut butter and maple syrup until evenly combined and smooth.
Stir in coconut flour. The dough will get thick, dry, and difficult to stir with a spatula, so use your hands to knead the dough and form a ball.
Evenly press the peanut butter dough ball all over the prepared pan. You want to fully cover the pan in an even layer of peanut butter dough. Smoothen the top of the layer using the back of a spoon.
Freeze while you prepare the chocolate ganache.
In a small mixing bowl, add the pieces of 70% vegan dark chocolate with melted coconut oil and peanut butter.
Melt under bain-marie or in the microwave by 30-second bursts, stirring between to prevent the chocolate from burning. It is ready when all the chocolate is melted, and the mixture is shiny and smooth.
Remove the baking dish from the freezer and pour the chocolate ganache over the peanut butter layer.
Spread evenly with a spatula.
Return the pan to the freezer for 10 minutes or until the chocolate ganache is set.
Slice the whole batch into 16 peanut butter bars.
Store bars in the fridge in an airtight container for 1 week or freeze. Defrost 2 hours before eating at room temperature or enjoy half frozen. Note that the peanut layer dries out slightly after freezing. The texture will be closer to a shortbread be still delicious.
Coconut flour swap: if you don't like coconut flour, you can replace the cup of coconut flour in the recipe with 2 cups of fine oat flour (not coarse!) The texture of the bars will be softer and slightly gritty.If you are on a low-carb diet, use sugar-free monk fruit syrup, net carbs per bar will be 8g.