Preheat your oven to 400°F (200°C).

Cut the celery into thirds and arrange on a baking sheet. Drizzle with olive oil and season with salt and pepper. Roast for about 30 minutes until tender and caramelized.

In a large pot, heat olive oil over medium heat. Sauté sliced mushrooms for 8-10 minutes until golden. Add diced potatoes, salt, pepper, and thyme. Cook for an additional minute.

Pour in water or vegetable stock, bring to a boil, then simmer for about 20 minutes until potatoes are fork-tender.

Carefully blend half of the cooked potatoes with the roasted celery and a few spoonfuls of broth until smooth.

Return blended mixture to the pot. Bring to a boil again, add elbow pasta, and cook until al dente. Adjust seasoning as needed.

Serve warm, garnished with fresh herbs and a drizzle of olive oil if desired.