Toast the sunflower seeds: Pour the sunflower seeds into a medium skillet over medium heat. Cook, stirring frequently (careful, they’ll burn!), until the seeds are turning golden on the sides, about 5 minutes. Pour the toasted seeds into a large serving bowl.
Add the chopped broccoli, onion, cheese, apples and cranberries to the serving bowl. Set aside.
In a 1-cup liquid measuring cup or small bowl, combine all of the dressing ingredients (olive oil, vinegar, mustard, honey, garlic and salt). Whisk until the mixture is well blended.
Pour the dressing over the salad and stir until all of the broccoli is lightly coated in dressing. I highly recommend letting the salad marinate for at least 20 minutes, or even overnight in the refrigerator.
Divide the salad into individual bowls and serve. Leftovers will keep well for 3 to 4 days in the fridge, covered.