Makes: 20 skewers at 61¢ each. Prep Time: 20 minutes. Cook: 3 to 4 minutes. Broil: 6 minutes.
Heat broiler. Coat broiler-pan rack with nonstick cooking spray. Soak twenty 6-inch bamboo skewers in warm water for 15 to 20 minutes.
Meanwhile, in batches, cook bacon in skillet over medium heat 3 to 4 minutes, until still flexible but lightly cooked. Transfer to plate; let stand until cool enough to handle.
Mix salt, allspice, cloves, black pepper, cinnamon and red pepper in small bowl; toss 1 teaspoon with shrimp in medium-size bowl.
Spread 1 strip bacon on work surface. Top with 1 shrimp; tuck pearl onion into curl of shrimp. Wrap with bacon to enclose shrimp and onion; secure with soaked skewer. Repeat with remaining bacon, shrimp, onions.
Whisk together corn syrup, maple extract and vanilla in a small bowl. Stir in remaining spice mixture. Divide in half; set half aside for dipping. Brush some of remaining syrup mixture over bacon-wrapped shrimp.
Broil skewers 1 inch from heat, for 3 minutes. Remove from broiler; carefully turn over. Brush with any remaining syrup mixture. Broil another 3 minutes or until bacon is crispy and shrimp cooked through. Serve with reserved syrup on the side for dipping.