From my story Another Bowl and Spoon “thing”
Makes 9 x 2 ¾” brownies.
1/3 cup canola oil
1 tsp vanilla extract
1 cup sugar
¼ tsp baking powder
½ cup cocoa powder
½ cup all purpose flour
¼ cup semi-sweet chocolate chips
Prepare an 8” x 8” square cake pan by thoroughly greasing it. Preheat the oven to 350˚F.
Break the egg into a very large bowl. Using a wooden spoon beat the egg until it is smooth, about thirty seconds.
Add the oil, and vanilla extract. Beat with the spoon until combined and smooth. Add the sugar, and continue beating with the spoon until the sugar is absorbed and the mixture is smooth. Then add the flour, salt, and baking soda and stir gently until combined.
Reserve three tablespoons of the batter in a small bowl or cup.
Add the cocoa powder to the batter in the large bowl and mix thoroughly until it has absorbed into the batter. Add the chocolate chips and stir until combined. Transfer the batter to the prepared cake pan.
Add the reserved batter from the small bowl in three stripes across the top of the batter in the cake pan. Using a knife, swirl the stripes so they have a marbleized appearance.
Bake in the pre-heated oven for about 25 minutes, or until the brownies have begun to pull away from the sides of the pan.
Cool completely before serving.