Combine mayonnaise, sugar, and vinegar in a small mixing bowl

Stir until the mixture is creamy

Cut up broccoli into bite-sized pieces

Chop the onion

Chop the bacon into small pieces

In a medium saucepan, cook the bacon until crisp (about 7 minutes)

Combine the broccoli, onion, bacon, and sunflower seeds in a medium bowl

Pour the dressing over the broccoli mixture

Stir until ingredients are combine

Serve