Spray a large saucepan with low calorie cooking spray and place over a medium heat. Add the onions, garlic and chopped broccoli stalk and cook for 5 minutes until the onion begins to soften.
Add the potato, broccoli florets and stock. Bring to the boil and then reduce to a simmer and place the lid on the saucepan for 15 minutes. When it’s ready the potatoes will be tender.
Remove the lid and add the Stilton. Stir until it has melted.
Remove the pan from the heat and blitz the soup with a hand blender until smooth.
Season with salt and pepper to taste and serve.