Add water and milk to a microwave-safe bowl. Heat in 10-second increments until just warm. This will prevent the melted coconut oil from solidifying once mixed with these liquids.
In a medium bowl, whisk together all wet ingredients: water, milk, coconut oil, coconut sugar, maple syrup and vanilla. Whisk until well incorporated.
Add wet ingredients to dry ingredients. Whisk until just incorporated, making sure no flour patches remain. Batter will be thick and liquidy—thick enough to be a bit stiff and easily scooped, but still liquidy enough to settle. Fold in chopped paleo chocolate chunks.
Using a large ice cream scoop, scoop and drop batter evenly into prepared muffin pan—filling each cup about 3/4 of the way for a greater quantity of medium dome-topped muffins, or all the way for a lower quantity of high dome-topped muffins. Makes 9 large muffins, or 12 medium muffins.
Bake for 19-25 minutes. Mine took 23 minutes for 9 high, dome-topped muffins. Insert a toothpick to test for doneness—it should come out mostly dry, with a few muffin bits on it.*
Place muffin pan on a cooling rack to cool for 30 minutes. Remove muffins from pan and continue cooling on rack until completely cool. Enjoy! Storing instructions below.
*Smaller muffins will take a shorter amount of time to bake--closer to 19 minutes.
Storing Notes: Store in an airtight container at room temperature for up to 1 week.
Freezing Instructions: Store muffins in an airtight, freezer-friendly container for up to 1 month. Allow to thaw at room temperature for 15-40 minutes before enjoying.