Cook the bacon in a skillet over medium-high heat until it's completely crisp, about 8-10 minutes, stirring occasionally. Transfer to a paper towel-lined plate to cool, then crumble into bite-sized pieces. While the bacon cooks, bring a pot of salted water to a boil. Add the broccoli florets and cook for exactly 3 minutes—this gives you tender-crisp broccoli with a slight bite. Drain immediately and rinse with cold water to stop the cooking process and preserve the bright green color.

In a large mixing bowl, combine the mayonnaise, Dijon mustard, cider vinegar, sugar, and finely diced onion. Whisk these together until smooth and well combined—the mustard acts as an emulsifier and adds a subtle tang that balances the sweetness. I like to taste the dressing at this point and adjust the sugar or vinegar if needed; some prefer it tangier, others sweeter, so trust your palate. Gently stir in the raisins, which will soften slightly as they absorb the dressing flavors.

Add the cooled broccoli from Step 1 to the dressing base from Step 2, folding gently with a spatula to ensure every piece gets coated without breaking the florets. Transfer the salad to a serving bowl or storage container and refrigerate for at least 1 hour—this chilling time allows the flavors to meld and the broccoli to fully absorb the creamy dressing. I find that making this salad a few hours ahead, or even the day before, improves the flavor since the broccoli becomes more tender and the dressing penetrates deeper.

Just before serving, stir in the crumbled bacon from Step 1 and the sunflower seeds. Adding these at the last minute keeps the bacon crispy and the seeds crunchy rather than getting soggy from sitting in the dressing. Give everything a gentle toss to distribute the crunchy elements throughout, then serve immediately.