Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.
In a large bowl, combine the almond flour, coconut sugar, baking soda, and salt. Stir until well mixed.
In a separate bowl, whisk together the melted coconut oil (or applesauce), vanilla extract, and egg (or flax egg). Once combined, add the wet ingredients to the dry ingredients and mix until a dough forms.
If using slivered almonds or dark chocolate chips, gently fold them into the dough until evenly distributed.
Scoop out tablespoon-sized portions of dough and roll them into balls. Place them on the prepared baking sheet and gently flatten each ball with your fingers or the back of a spoon.
Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden. Be careful not to overbake, as almond flour cookies can become dry if cooked too long.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.