Dry Ingredients Wet Ingredients Frosting (Optional)

For The Cake

1. Raise oven temperature to 350 degrees. Lightly coat an 8x8 square pan with nonstick spray.
2. Mix the first five dry ingredients in the prepared pan (flour, cocoa powder, sugar, baking soda, and salt).
3. Form three depressions in the dry ingredients - two small, one larger.
4. Pour vinegar into one of the smaller depressions. Pour vanilla extract into the other smaller depression, and pour vegetable oil into the third larger depression.
5. Pour water over everything. Mix thoroughly until smooth.
6. Bake in the center of the oven for 35 minutes. Insert a toothpick into the center of the cake to check for doneness. Note: Oven baking times vary, so check the cake regularly to avoid overbaking.
7. Cool completely before frosting (if using). You can also sprinkle with powdered sugar instead of frosting.

For The Frosting

1. Combine chocolate chips, evaporated milk, butter, and vanilla extract in a microwave-safe bowl.
2. Microwave on high for 30 seconds. Note: It can be difficult to tell if everything has melted, so check. If it's not melted, microwave for an additional 15 seconds and stir. Repeat this process until completely melted.
3. Mix in powdered sugar until smooth and combined.
4. Frost the cooled cake.