Preheat oven to 350°F or 180°C.
Cream the butter and sugar together before mixing in the eggs and vanilla extract.
Combine the baking soda, flour, cocoa, salt and cinnamon together in a bowl.
Add the powdered ingredients gradually to the egg mixture and mix.
Stir in the oatmeal flakes and pecans.
Drop the dough in heaping teaspoonfuls onto a greased baking sheet.
Bake for 15 to 18 minutes.