Preheat oven to 350°F /180°C.
In a large bowl mix together oil and sugar.
Add eggs, chocolate milk powder, sour cream, and rising flour.
Heavily grease the pan with oil or butter.
Pour the batter into the pan and bake for about 45-55 minutes, until the cake is firm, and a toothpick comes out almost completely dry (with moist crumbs). Cool completely before frosting.