Clean and slice the leek. Fry the bacon cubes in a large saucepan until crispy and take them out again. Braise the leek rings in the bacon fat. Deglaze with the meat stock and cook for about 10 minutes. Then stir in the milk and the mashed potato powder and reheat. Season to taste with a little cream, salt and pepper. If you want, you can also add a pinch of nutmeg.
Before serving, sprinkle the bacon cubes over each serving.