In a large pan over medium-high heat, fry the diced potatoes and diced carrots with the paprika powder, white pepper, and curry powder for 3-4 minutes until they begin to color, then remove with a slotted spoon and set aside.
In the same pan over medium heat, fry the thinly sliced leek for 3-4 minutes until lightly browned.
Add the reserved potato and carrot mixture back to the pan, pour in the vegetable stock, and bring to a boil over high heat.
Finely mash the floury potato and stir it into the boiling soup to thicken.
Reduce heat to medium-low, cover, and simmer gently for 15-20 minutes.
Stir in the whipped cream and finely chopped parsley, season to taste with salt, and serve.