Cut the broccoli into bite-sized pieces. If using whole broccoli heads, cut off the florets. Slice off the bottom of the stalk. Slice lengthwise down one side of the stalk to remove the outer layer. Rotate the stalk onto the flat cut side and repeat until you've sliced off all of the outer layer. Cut the stalk crosswise into ¼" pieces.
To blanch the broccoli (optional but recommended): Bring a large saucepan of salted water to a boil. Carefully drop in the broccoli. After 30-60 seconds (depending on how small you cut the broccoli; do not go longer than 60 seconds), drain the broccoli and plunge into a bowl of ice water. Let cool completely. Drain and dry on a towel or paper towels.
Meanwhile, cook the bacon until just crisp. Drain on a paper towel-lined plate, then dice.
In a medium bowl, whisk together the mayonnaise, maple syrup or apple juice, and vinegar.
Add the broccoli to a large bowl. Add the sunflower seeds, raisins, diced red onion and bacon.
Pour over the dressing and toss until everything is evenly coated. Serve at room temperature or chill in the fridge for at least an hour to serve cold. Stir occasionally to redistribute the dressing.