Heat the oven to 425 degrees. Coat a large, rimmed baking sheet with nonstick cooking spray.
Toss the cauliflower, olive oil and 1/4 teaspoon salt in a large bowl to coat. Arrange the cauliflower on the baking sheet.
Combine the hot sauce and melted butter in a small cup. Bake for 20 minutes or until the cauliflower is brown on the bottom and starting to soften.
Drizzle the hot sauce mixture over the cauliflower and stir to coat. Continue baking for 5 minutes or until the cauliflower is browned and crisp-tender.
Meanwhile, combine the cottage cheese, blue cheese, sour cream, mayonnaise, lemon juice, remaining salt, and black pepper in a small bowl.
Serve the cauliflower warm or at room temperature with the dip.