Preheat your oven to 350°F (175°C) and line a baking tray with parchment paper.
In a large mixing bowl, combine the almond flour, coconut flour, baking soda, salt, and sugar substitute. Mix well to ensure there are no clumps.
In another bowl, whisk together the applesauce, melted coconut oil, and vanilla extract until smooth.
Pour the wet ingredients into the dry ingredients and mix until just combined. If you’re making muffins, gently fold in the blueberries now.
For cookies, fold in the sugar-free chocolate chips at this stage.
Spoon the batter onto the prepared baking tray, spacing them about 2 inches apart. If making muffins, fill each cup about 2/3 full.
For muffins, bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean. For cookies, bake for 10-12 minutes until the edges are lightly golden.
Remove from the oven and allow to cool on the tray for 5 minutes before transferring to a wire rack to cool completely.