Found this on AllRecipes...I substituted Splenda for the white sugar. Here is the original recipe:

Ingredients

2 cups unbleached all-purpose flour

2 cups white sugar

3/4 cup unsweetened cocoa powder

1 teaspoon baking powder

1 teaspoon salt

1 cup Water

1 cup vegetable oil

1 teaspoon vanilla extract

Directions

Preheat the oven to 350 degrees F (175 degrees C).

In a large bowl, stir together the flour, sugar, cocoa powder, baking powder and salt. Pour in water, vegetable oil and vanilla; mix until well blended. Spread evenly in a 9x13 inch baking pan.

Bake for 25 to 30 minutes in the preheated oven, until the top is no longer shiny. Let cool for at least 10 minutes before cutting into squares.

Nutritional Information

Amount Per Serving Calories: 284 | Total Fat: 14.3g | Cholesterol: 0mg

Sounds good to me. Think I may try it.