Steam broccoli florets for 2-3 minutes until tender-crisp. Transfer to an ice bath to stop cooking, then drain thoroughly and pat dry.
Cook bacon strips until crispy, about 5-7 minutes. Drain on paper towels and crumble when cooled.
In a large mixing bowl, whisk together mayonnaise, apple cider vinegar, salt, pepper, and garlic powder (if using) until smooth.
Add the cooled broccoli florets to the bowl with the dressing, ensuring the broccoli is completely dry.
Add crumbled bacon, shredded cheddar cheese, diced red onion, and sunflower seeds to the bowl.
Gently fold all ingredients together until everything is evenly coated with dressing.
Taste and adjust seasoning if needed.
Cover and refrigerate for at least 30 minutes before serving to allow flavors to meld.
Give the salad a final toss before serving.
