Cut the broccoli into small bite-sized florets and set aside. Finely dice the red onion and set aside. Measure out the mozzarella and cheddar cheese, then combine them in a small bowl. Measure the sunflower seeds and set everything within arm's reach—this salad comes together quickly once you start mixing.

Cook the bacon slices in a skillet over medium-high heat until they're brown and crispy, about 8-10 minutes. Transfer to a paper towel-lined plate to cool slightly, then crumble into bite-sized pieces. I like to leave the bacon slightly chunky rather than powdery—it gives you nice texture bites throughout the salad.

In a large mixing bowl, whisk together the mayonnaise, vinegar, sugar, salt, and pepper until smooth and well combined. The vinegar will help cut through the richness of the mayo and cheese, creating a balanced flavor. Taste and adjust seasoning if needed.

Add the broccoli florets, crumbled bacon from Step 2, combined cheeses from Step 1, red onion, and sunflower seeds to the bowl with the dressing. Toss everything together until all the broccoli is evenly coated with the dressing. I recommend using a rubber spatula to gently fold and mix rather than stirring aggressively—this keeps the broccoli florets intact and looking fresh.