1. Add the bacon to a large skillet and cook over medium heat, stirring occasionally, until crisp, 8 to 10 minutes. Drain on a paper-towel-lined plate.
2. In a large bowl, toss together the broccoli florets, shallot, sunflower seeds, cranberries and cooked bacon.
3. In a small bowl, whisk together the Greek yogurt, mayonnaise, sugar, vinegar, 1 teaspoon salt and 1 teaspoon pepper.
4. Add the dressing to the broccoli mixture and gently toss to coat. Taste and adjust the seasoning as needed. The salad can be served at room temperature or chilled, and will keep in an airtight container in the refrigerator for about 5 days.