Preheat the oven to 325°F and line a large baking sheet with parchment paper.
In a large mixing bowl, whisk together the dry ingredients: oats, coconut sugar, oat flour, coconut flour, chia seeds, salt, cinnamon, baking soda, and cream of tartar.
In a separate bowl, mix the wet ingredients: almond butter, melted coconut oil, maple syrup, and vanilla. Stir until smooth and well combined.
Pour the wet ingredients into the dry and stir until everything is evenly coated. The mixture should be slightly sticky and clumpy.
Spread the mixture evenly on your baking sheet. Press it down gently with the back of a spoon or spatula if you want more granola clusters.
Bake for 20 minutes, then gently stir and rotate the pan. Bake for another 10–15 minutes or until golden and fragrant. (The granola will crisp up as it cools.)
Remove from the oven and let it cool for 10–15 minutes. Once the granola is still warm but not hot, gently stir in the chocolate chunks. This helps them melt just enough to bind to the granola without turning into a full chocolate coating.
Let the granola cool fully before storing. It will crisp up as it cools. Break into clusters.
Notes
Store the granola in an airtight container at room temperature for up to 2 weeks (if you don't devour it before then!).