Preheat your oven to 350°F (175°C) and prepare your muffin tin by greasing it lightly or lining it with muffin liners.
In a large mixing bowl, whisk together the rolled oats, cocoa powder, coconut palm sugar, cream of tartar, baking powder, baking soda, and salt until well combined.
In another bowl, mix the melted coconut oil, unsweetened applesauce, vanilla extract, Greek yogurt, and hot water. Stir until the mixture is smooth and creamy.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Be careful not to overmix; a few lumps are perfectly fine.
Gently fold in the chocolate chips and coconut flakes to the batter, ensuring an even distribution throughout.
Scoop the batter into the prepared muffin tin, filling each cup about 3/4 full to allow for rising during baking.
Place the muffin tin in the preheated oven and bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.
Once baked, let the muffins cool in the tin for about 5 minutes before transferring them to a wire rack. Enjoy warm or store for later!