Preheat the oven to 180 degree celsius.

Combine the potato cubes with olive oil, lemon juice, mixed herbs, and red chilli flakes in a mixing bowl.

Place the potatoes on a tray lined with aluminum foil and roast for 30 mins, tossing occasionally.

Heat butter in a saucepan on medium flame.

Add flour and cook until it turns light brown.

Whisk in the milk until the sauce thickens to a pouring consistency.

Turn off the flame and add grated cheddar cheese, whisking until combined.

Add white pepper powder and salt to taste.

Stir in sour cream and spring onion greens.

Thin with water if necessary.

Add the roasted potatoes to the soup.

Preheat the oven to 200 degree celsius.

Cut a cavity in the sourdough bread and remove the insides.

Brush the inside of the bread with melted butter.

Bake the bread for 10 minutes until crusty.

Pour the soup into the bread bowl and serve.