In a large pot, heat olive oil over medium heat. Add chopped onion and minced garlic, sauté until soft.

Add broccoli florets and vegetable broth. Bring to a boil, then reduce heat and let simmer until broccoli is tender, about 10-15 minutes.

Use an immersion blender to puree the soup until smooth.

Stir in the milk or cream and shredded cheddar cheese until melted.

Season with salt and pepper to taste.

Serve warm, garnished with croutons if desired.