1. Draw a round cake bottom, which is slightly flat.

2. Draw traces of ketchup on the bottom of the cake, which can be scattered or wavy.

Draw the ingredients of pizza, such as green pepper, onion, mushroom, bacon and so on. And outline their shapes with simple lines.

Draw the cheese of pizza on the bottom edge of the cake and outline its shape with lines.

5. Color the pizza with a colored pen to make it look more vivid.

By following these steps, you can draw a simple and beautiful pizza and try different painting methods and color matching to make your work more personalized.