In a large bowl, combine the butter with the sugar. Add the eggs and mix well until combined. Add the oil and stir to combine.
In a separate bowl, whisk the flour, cocoa powder, baking powder, and salt. Add the flour mixture to the wet ones and stir until combined. Chill the dough in the refrigerator for an hour which will make it easier to handle.
If you want giant cookies like mine, form the dough into 1" balls. If you want smaller cookies, use about a teaspoon of dough to form the balls. Roll each ball in the powdered sugar and place the balls on a baking sheet spaced about 2 inches apart.
Bake the cookies for 12-15 minutes. The cookies will spread a lot as they bake. Cool the cookies on the baking sheet for a few minutes before transferring them to a baking rack to cool completely. Store the cookies in an airtight container.
Notes
How to Freeze the Cookie Dough
If you want to freeze the cookie dough to bake later you can make the cookie dough balls and place them on a sheet pan. Freeze them on the sheet pan and, once frozen, transfer the balls to an airtight container.
When you are ready to bake the cookies, thaw the dough balls at room temperature. This will only take 15 to 20 minutes. Roll the dough balls in the powdered sugar and bake for 12 to 15 minutes.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.