Drain sweet potato syrup directly into a large skillet, reserving sweet potatoes.
Add brown sugar, butter and salt to syrup; bring to a boil over high heat.
Reduce heat to medium-high and boil until liquid is reduced and thickened and a deep golden brown, about 20 minutes.
Reduce heat to medium and carefully add sweet potatoes to hot syrup. Stir gently to coat potatoes in syrup. Heat about 5 minutes, stirring gently occasionally.
Notes
VARIATIONS: To make a variety of sweet & savory candied sweet potatoes, prepare recipe as directed, except:Honey Jalapeno Sweet Potatoes - Add 1 Tbsp. honey and 1 to 2 Tbsp. finely chopped fresh jalapeño in Step 2.Spicy Garlic Sweet Potatoes - Add 1 minced garlic clove and 1/8 to 1/4 tsp. red pepper flakes in Step 2.Maple Onion Sweet Potatoes - Add 2 Tbsp. maple flavored syrup and ½ cup chopped onion in Step 2.Spiced Sweet Potatoes - Add 1/4 tsp. cinnamon or pumpkin pie spice and 1/4 tsp. cracked black pepper in Step 2.