Preheat oven to 375 degrees. In a bowl mix together butter, brown sugar and white sugar until light and fluffy. Beat in eggs, one at a time, add vanilla. Stir in oatmeal. Sift flour, baking powder, baking soda into the mix. Stir together until combined. Add in pecans and white chocolate chips. Bake at 375 for 10-12 minutes. If you want a chewy cookie bake 9-10 minutes.