In a large pot, heat the olive oil over medium-high heat. Add the onions and garlic and sauté until the onions are translucent, about 5 minutes.
Add the potatoes, broccoli, and vegetable stock to the pot. Bring to a boil, then reduce the heat and simmer for 10-15 minutes, until the potatoes and broccoli are tender.
Remove the pot from the heat and carefully transfer the soup to a blender. Blend until smooth and creamy.
Return the blended soup to the pot and stir in the cream. Season with salt and pepper to taste.
Serve the soup hot, topped with grated cheese, croutons, and crusty bread, if desired.