01 - Preheat the oven to 350°F. Line a 12-cup muffin pan with paper liners or lightly grease each cup.
02 - In a large bowl, whisk together old-fashioned rolled oats, almond flour, cocoa powder, sea salt, and baking powder.
03 - In a separate bowl, whisk melted coconut oil, maple syrup, packed brown sugar, eggs, and vanilla extract until fully incorporated.
04 - Pour the wet mixture into the bowl with the dry ingredients. Stir gently with a spatula until just blended.
05 - Fold in dark chocolate chips and chopped walnuts or pecans, if using, ensuring even distribution.
06 - Spoon the mixture evenly into the prepared muffin tin, filling each cup approximately three-quarters full.
07 - Bake for 18 to 20 minutes or until the centers are set and a toothpick inserted in the center comes out mostly clean with melty chocolate streaks.
08 - Allow the oatmeal cups to cool in the pan for 10 minutes. Transfer to a wire rack to cool completely before serving.