1. Preheat oven to 350degreesF. Spray an 8-inch square baking pan with vegetable cooking spray.
2. In the top of a double boiler or in a heatproof bowl over barely simmering water, melt 1/3 cup of the chocolate chips with the oil, stirring occasionally until smooth. Remove from heat and stir in the cocoa until smooth. Let cool about 10 minutes.
3. In a large mixing bowl, whisk together the whole egg and egg whites. Add the sugar and whisk to combine, or use an electric mixer on low speed. Add the vanilla and the chocolate-oil mixture and mix with a wooden spoon until smooth.
4. In a separate bowl, stir together the flour, baking powder, and salt. Fold into the chocolate mixture and stir until well blended, about 2 minutes. Stir in remaining 1/2 cup chocolate chips.
5. Pour batter into prepared pan and bake for 25 to 30 minutes, until a toothpick inserted in the center comes out clean. Remove from the oven and cool for at least 10 minutes before cutting into 2-inch squares. Serve warm or at room temperature.
Source: fresh Magazine May, June 2010