Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, whisk together the almond flour, coconut flour, chia seeds, baking soda, and salt.

In a separate bowl, whisk together the egg (or flax egg), melted coconut oil, maple syrup, lemon juice, lemon zest, and vanilla extract.

Pour the wet ingredients into the dry mixture and stir gently until well combined. Let the batter rest for about 5 minutes.

Use a tablespoon or a cookie scoop to form 1.5-inch rounds of cookie dough. Flatten each cookie slightly.

Bake the cookies in the preheated oven for 10–12 minutes, or until the edges are golden brown. Allow to cool for about 5 minutes.

Serve fresh or store them in an airtight container for later use.