Preheat vegetable oil in a heavy-bottomed pot or Dutch oven to 175°C (350°F).
For the spring rolls: Add mashed potato, chopped crispy bacon, chopped chives, sour cream, butter, salt and freshly ground pepper in a bowl and mix to combine.
With your spring roll wrapper laid out in a diamond shape in front of you, add about 1½ tablespoons of the potato mixture in the centre.
Roll the bottom point up and over the contents; fold each side over the middle; paint the top corner with cornstarch mixed with water and seal.
Repeat with remaining wrappers and filling.
Carefully transfer some of the spring rolls into hot oil and fry for 3-5 minutes, or until crispy and golden.
Work in batches to not overcrowd the pot.
Transfer to a paper towel-lined plate. Set aside.
For cheese dip: Add cream cheese, smoked cheddar (or gouda) and cream to a small saucepan and cook over medium-low heat, stirring frequently, until melted and creamy.
Transfer to a small serving dish and serve alongside spring rolls.
