01 -
Heat the oven up to 220°C. Lay the celery and potatoes on a baking tray. Toss them with 2 tablespoons of olive oil and add salt and pepper.
02 -
Roast for 25-30 minutes. Flip them once midway, until they're tender and have golden edges.
03 -
Warm 1 tablespoon of olive oil in a big pot over medium heat. Add in onions and cook for 5 minutes until they soften. Then toss in garlic and thyme, cooking just another minute.
04 -
Pour the roasted celery and potatoes into the pot with the veggie broth. Heat it to a boil, then simmer gently for 10-15 minutes.
05 -
Blend the soup until it's velvety and smooth, using an immersion blender. If you're using a normal blender, do it in batches carefully.
06 -
If you'd like, mix in the heavy cream, and adjust the salt and pepper to your taste.
07 -
Serve it warm, topped off with chopped parsley or chives.