In large soup pot, add olive oil over medium-high heat.
Add onion, leeks, carrots, celery, garlic, and potatoes, season with salt and pepper, and cook until softened, about 10-12 minutes.
Add thyme and vegetable broth, and bring to a simmer.
Reduce heat and let cook for 15 more minutes, until potatoes are softened.
Using an immersion blender or high-powered blender, puree until smooth.
To make the croutons:
Preheat oven to 375 degrees F.
Add olive oil to a bowl, then add bread cubes, tossing to coat.
Toss with cheese and season with salt and pepper.
Place on baking sheet and bake in preheated oven for 8-10 minutes, until golden.