Chocolate Oatmeal Peanut Butter Chip Cookies

My family has two classic cookie recipes. This is the more special, less commonly made one of the two. It's my brother's favorite, and it's what I made tonight.

1 cup butter
1 1/2 cups sugar
2 eggs
2 tsp vanilla
1 1/2 cups flour
1/2 cup cocoa
3/4 tsp baking soda
1/2 tsp salt
2 cups oatmeal
2 cups peanut butter chips

Cream butter and sugar. Add eggs and vanilla; beat well. Combine flour, cocoa, baking soda and salt, and add to creamed mixture. Stir in oatmeal and peanut butter chips. Bake on an ungreased cookie sheet at 350 for 9-12 minutes.