Heat a little oil in a large saucepan, add the garlic, paprika, mushrooms and diced potatoes, sauté for 2 to 3 minutes, stirring from time to time.
Season with salt and freshly ground black pepper.
Pour in the stock and leave to simmer for 10 minutes.
Pour into a blender and puree until smooth.
Preheat the oven to 190°C/fan 170°C/gas 5.
For the croutons, place the torn bread pieces onto a baking tray.
Drizzle over the oil, season with salt and pepper.
Add the nori shreds and sesame seeds and mix well.
Bake for about 10 to 12 minutes, turning from time to time, keep an eye on them.
Ladle into soup bowls and serve with the croutons.