Preheat the oven: Set your oven to 350°F (175°C). Grease and flour your cake pan or line it with parchment paper for easy removal.
Mix the dry ingredients: In a large mixing bowl, combine the pancake mix with sugar (if using) and cocoa powder (for chocolate cake) until evenly distributed.
Add the wet ingredients: Crack the eggs into the bowl, then pour in the milk and oil. Add the vanilla extract if desired. Mix everything together using a whisk or electric mixer on low speed until the batter is smooth and well combined.
Optional add-ins: If you’re adding extra flavor like chocolate chips, berries, or nuts, fold them into the batter.
Bake the cake: Pour the batter into your prepared cake pan. Bake for 25 to 30 minutes or until a toothpick inserted into the center comes out clean.
Cool and serve: Let the cake cool in the pan for 10 minutes, then transfer it to a cooling rack to cool completely before frosting or serving.