Opa's Chocolate Chip Cookies

These are delicious cookies that make really good ice cream sandwiches.  That's what we made them for, and we had a hard time not eating them all before that.  This is my Opa's (Grandpa's) recipe.  We only made a half recipe because the whole one makes a lot. 

Opa's Chocolate Chip Cookies
from my Opa; this is a half-recipe

1 cup butter, softened
1 cup brown sugar
1 cup white sugar
1 teaspoon vanilla
2 eggs
2 1/2 cups flour
1 1/2 cups oatmeal (like quick oats)
1/2 teaspoon salt
1 teaspoon baking soda
1 teaspoon baking powder
1 (10-12 oz) package chocolate chips
3/4 cups chopped walnuts or pecans, optional

1.  Preheat oven to 400 F.  Mix butter, sugars, vanilla and eggs.  Mix well until smooth.  Add flour, salt, baking soda, baking powder, and oatmeal.  Mix in.  Stir in chocolate chips and nuts.  Shape into golf ball size balls and mash down slightly on lightly greased cookie sheet.  Bake 6-8 minutes.  Do not overbake.  Makes about 3 dozen.