In a large mixing bowl, cream together the butter, shortening, sugar, and brown sugar until light and fluffy with a mixer for about 3-4 minutes. Add the eggs and vanilla and mix well.
Combine the flour, baking soda, baking powder, and salt in a bowl. Add the flour mixture to wet ingredients and mix just until combined.
By hand, stir in the old-fashioned oats, rice krispies cereal, coconut flakes, and chopped pecans. The cookie dough will be very thick, crumbly even.
When ready to bake, preheat the oven to 350° F and prepare cookie sheets by lining with parchment paper or a silicone baking mat.
Scoop the cookie dough into balls and place on the cookie sheets. If using whole pecans as garnish, gently place one pecan in the center of each cookie and press down slightly but do not flatten the cookies.
Bake for about 10-12 minutes, or until cookies are slightly puffed and light golden on the edges. Carefully transfer to cooling racks to cool.