SAUTÉ bacon in a large skillet over medium-high heat until crisp; remove and drain bacon, reserving drippings in skillet. Add shallots to skillet, and sauté until tender; remove from skillet. Add spinach, and sauté 4 to 5 minutes or until wilted. Set aside.
COMBINE mashed potatoes, milk, and butter in a 2-quart microwave-safe bowl. Microwave at HIGH 15 minutes, stirring once. Let stand 2 minutes. Stir in bacon, shallots, and half of crumbled blue cheese.
ARRANGE spinach around edges of a serving plate. Spoon potatoes in center, and sprinkle with remaining blue cheese. Makes 4 to 6 servings.