01 - Preheat the oven to 350°F. Line a 12-cup muffin tin with paper liners or lightly grease with nonstick spray.
02 - In a large bowl, mix the oats, almond flour, cocoa powder, sea salt, and baking powder until well combined.
03 - In a medium bowl, whisk together the melted coconut oil, maple syrup, brown sugar, eggs, and vanilla extract until smooth and emulsified.
04 - Pour the wet ingredients into the dry ingredients. Stir gently with a spatula until just combined, being careful not to overmix.
05 - Gently fold in the dark chocolate chips and chopped nuts, if using, until evenly distributed throughout the batter.
06 - Divide the mixture evenly among the prepared muffin cups, filling each about three-quarters full.
07 - Bake for 18 to 20 minutes, or until the centers are set and a toothpick inserted comes out mostly clean with a few melty chocolate streaks.
08 - Let cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before serving.