Preheat oven to 400°F (200°C). Mix ¼ cup (60 mL) of the brown sugar, orange juice, vanilla, ½ tsp (2 mL) each of the cinnamon and ginger, and salt in a large bowl. Add sweet potatoes; toss to coat well. Spoon into 13x9-inch (33x23 cm) baking dish. Sprinkle evenly with cranberries. Dot with 2 tbsp (30 mL) of the butter. Cover with foil. Bake 30 minutes.