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