Nonstick cooking spray, for spraying the baking pan
1 cup granulated sugar
1 cup dark brown sugar
2 teaspoons vanilla extract
1/2 teaspoon kosher salt
2 large eggs plus 2 yolks
1 stick (8 tablespoons) unsalted butter, melted
8 ounces semisweet chocolate chips
1/2 cup vegetable oil
1 1/4 cups all-purpose flour
1/4 cup cocoa powder