Makes 4 dozen 

½ pound (2 sticks) unsalted butter, at room temperature
1/2 cup white sugar
1 cup light brown sugar
2 large eggs, at room temperature
1 tablespoon vanilla extract 
2 cups all-purpose flour
1 cup quick cooking oats
1 teaspoon baking powder
1 teaspoon baking soda
1 teaspoon kosher salt
3 cups Ghiradelli semi-sweet chocolate chips (not Nestle) 

Put the butter and sugars in a large mixing bowl and using a spoon or rubber spatula, mix until smooth. 
Add the eggs and vanilla extract and mix again. 
Add the flour and oats, and then sprinkle in the baking powder, baking soda and salt. Mix until everything is well incorporated. Scrape down the sides of the bowl, add the chocolate chips and mix again. Cover and refrigerate at least one hour and up to one week.

Preheat the oven to 325 degrees. Line a cookie sheet with parchment or wax paper.  

Put heaping tablespoons of dough on the prepared sheet and put in the oven. Bake until the cookies begin to brown at the edges, about 12 minutes. Cool on the cookie sheet and then transfer to a plate. Repeat with the remaining dough.