Cut the stems from the broccoli and set aside. Chop the florets into bite-sized pieces.
Put a couple of inches of water at the bottom of a large pot with steamer basket or mesh strainer inside. Once the water is boiling, add the broccoli florets, cover, and steam for one minute. You just want to take the raw edge off. Drain, rinse in let cool and dry with a clean kitchen towel.
Place the sunflower seeds in a small skillet over medium heat, and toast, stirring frequently, until they are lightly brown and fragrant.
Use a sharp knife or vegetable peeler to peel the tough skin from the broccoli stems, then shred, julienne, or finely dice the stems.
In a large bowl whisk together the mustards, honey, olive oil, and vinegar.
Add the broccoli florets, stems, toasted sunflower seeds, slidced grapes, and parsley into the bowl with the dressing and toss well. Taste, and then season with salt and pepper.
Transfer the salad into a serving bowl, and serve!