Directions

1. 1 Heat oven to 350°F (325°F for dark or nonstick pan). Spray bottom and sides of 9- or 8-inch square pan with baking spray with flour.
2. 2 In large bowl, beat cake mix, water, sour cream, butter and egg with electric mixer on low speed 30 seconds. Beat on medium speed 2 minutes, scraping bowl occasionally. Stir in 1/2 cup of the chocolate chips. Spread in pan.
3. 3 Bake 9-inch pan 22 to 28 minutes, 8-inch pan 27 to 33 minutes or until toothpick inserted in center comes out clean. Cool completely, about 1 hour.
4. 4 In small microwavable bowl, microwave 1/2 cup of the chocolate chips and the oil uncovered on High 45 seconds, stirring every 15 seconds, until melted. Place in small resealable food-storage plastic bag; cut off tiny corner of bag. Drizzle over top of cake. Sprinkle with remaining 1/4 cup chocolate chips. Store loosely covered.