Step 1: Preheat the Oven: Preheat oven to 350F (175C). Grease and flour a 9x13 inch baking pan, or prepare two 9-inch round cake pans. This prevents sticking.
Step 2: Combine Wet Ingredients: In a large mixing bowl, combine the Duncan Hines Yellow Cake Mix, water, vegetable oil, eggs, and vanilla extract (if using). Ensure all ingredients are at room temperature for best results.
Step 3: Mix the Batter: Using an electric mixer, beat the ingredients on low speed for 30 seconds, then increase to medium speed and beat for 2 minutes. The batter should be smooth and well combined, free of lumps. Avoid overmixing.
Step 4: Bake the Cake: Pour the batter into the prepared pan or pans and spread evenly. Bake for 30-35 minutes for a 9x13 inch pan, or 25-30 minutes for round cake pans, or until a wooden skewer inserted into the center comes out clean.
Step 5: Cool the Cake: Let the cake cool in the pan for 10 minutes before inverting it onto a wire rack to cool completely. Complete cooling ensures the cake is sturdy enough for frosting.
Step 6: Frost the Cake: Once the cake is completely cool, frost with your favorite frosting. Buttercream, chocolate ganache, or cream cheese frosting all complement yellow cake beautifully. Feel free to add sprinkles or other decorations.
Optional tip: For a richer flavor, substitute melted butter for vegetable oil. For a moister cake, add a tablespoon of sour cream or yogurt to the batter.