01 - Preheat the oven to 350°F. Line a 12-cup muffin tin with paper liners or lightly grease it.
02 - In a large bowl, mix the oats, almond flour, cocoa powder, sea salt, and baking powder until well blended.
03 - In another bowl, whisk together the melted coconut oil, maple syrup, brown sugar, eggs, and vanilla extract until smooth and uniform.
04 - Pour the wet ingredients into the dry mixture. Stir gently with a spatula until just combined, being careful not to overmix.
05 - Fold in the dark chocolate chips and chopped nuts if using, distributing them evenly throughout the batter.
06 - Divide the batter evenly among the prepared muffin cups, filling each about 3/4 full.
07 - Bake for 18 to 20 minutes, until the centers are set and a toothpick inserted comes out mostly clean. A few melty chocolate streaks are acceptable.
08 - Let the oatmeal cups cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before serving.