1. Bring first 4 ingredients to a boil in a saucepan; cover, reduce heat, and simmer 6 minutes or until potato is tender. Remove from heat. Let stand, uncovered, 10 minutes.
2. Heat a large skillet over high heat. Add oil; swirl to coat. Pat scallops dry with paper towels; sprinkle with 1/4 teaspoon salt and black pepper. Add scallops to pan; cook 3 minutes on each side or until desired degree of doneness. Remove scallops from pan.
3. Pour cauliflower mixture in a blender. Add 1/2 teaspoon salt, butter, and red pepper. Remove center piece of blender lid (to allow steam to escape); secure lid on blender. Place a clean towel over opening in lid (to avoid splatters). Blend until smooth. Serve puree with scallops.