Preheat oven to 200°C/180°C fan-forced. Line two baking trays with baking paper. Place pumpkin, garlic and oil in a bowl. Season with salt and pepper and toss to coat. Arrange pumpkin mixture, in a single layer, on prepared trays. Bake for 40 minutes or until pumpkin is golden and tender.
Squeeze garlic cloves from skin, discard skin and set aside. Melt butter in a large saucepan over medium-high heat. Add leek and cook, stirring, for 3 minutes or until leek has softened. Add potato and cook stirring, for 5 minutes.
Add stock and 2 cups of cold water. Season with pepper. Cover and bring to boil. Reduce heat to medium-low, simmering for 15 minutes or until potato is tender. Stir in roasted pumpkin and garlic. Cook for 5 minutes or until heated through. Set aside for 5 minutes to cool slightly.
Blend the pumpkin mixture until smooth. Ladle into serving bowls. Drizzle with cream and sprinkle with chives. Serve with toasted ciabatta slices.
