01 - Preheat the oven to 350°F. Line a 12-cup muffin tin with paper liners or lightly grease with cooking spray.
02 - In a large mixing bowl, combine the oats, almond flour, cocoa powder, sea salt, and baking powder. Mix until evenly distributed.
03 - In a separate medium bowl, whisk together the melted coconut oil, maple syrup, brown sugar, eggs, and vanilla extract until smooth and well blended.
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 batter evenly among the prepared muffin cups, filling each cup about 3/4 full.
07 - Bake for 18-20 minutes, or until the centers are set and a toothpick inserted comes out mostly clean with a few moist chocolate streaks.
08 - Let the oatmeal cups cool in the muffin tin for 10 minutes, then transfer to a wire rack to cool completely before serving.