Preheat oven to 350 Fahrenheit.
Grease a medium baking pan with cooking spray. set aside.
In a mixing bowl, combine butter, oil, and eggs. Beat until well blended.
Stir-in the sugar, flour, cocoa powder, vanilla extract, baking powder, and salt. Mix well.
Pour the mixture in the greased pan. Bake for 28 minutes. Note: in about 20 minutes of baking, sprinkle the chopped cashews evenly on top and continue to bake until the brownies are done.
Remove from the oven. Let is cool.
Serve. share and enjoy!