Brownie Cake
1 and ½ cups vegetable oil
3 cups sugar
3 teaspoons vanilla extract
6 eggs
1 and ½ cups flour
1 cup cocoa powder
¾ teaspoon baking powder
¼ teaspoon salt

Cookie Dough Filing
3 sticks unsalted butter, at room temperature
¾ cup light brown sugar, packed
3 and ½ cups confectioners’ sugar
1 cup all-purpose flour
¾ teaspoon salt
3 Tablespoons milk
2 and ½ teaspoons vanilla extract

Ganache Frosting
4 ounces semi-sweet chocolate, finely chopped (or use chocolate chips)
½ cup heavy whipping cream
¼ cup light corn syrup
2 teaspoons vanilla extract
Extra chocolate chips, for garnish