1. Peel sweet potatoes, and cut into 1-inch cubes. Cut onions into quarters, and cut each quarter in half.
2. Toss together sweet potatoes, onions, crushed garlic, and 2 Tbsp. olive oil; place on a lightly greased aluminum foil-lined 15- x 11-inch jelly-roll pan. Sprinkle evenly with salt and pepper.
3. Bake, stirring occasionally, at 400° for 45 minutes or until tender and lightly brown. Serve over spinach, and drizzle with Warm Bacon Dressing. Garnish, if desired.