Preheat your oven to 400°F (200°C). Take the celery stalk and trim off the root part before cutting it into thirds. Drizzle with 1 tablespoon of olive oil and season with salt and pepper. Spread the celery on a baking sheet and roast for 30 minutes, until it becomes tender and slightly caramelized, releasing a delightful aroma.

In a large pot, heat the remaining olive oil over medium heat. Add the sliced cremini mushrooms and sauté them for 8-10 minutes, stirring occasionally, until they’re browned and fragrant. Next, incorporate the diced Yukon Gold potatoes and thyme, allowing them to cook together for an additional minute.

Pour in 7 cups of water or vegetable stock and bring the mixture to a boil over high heat. Once boiling, reduce the heat to low and let it simmer for 20 minutes, until the potatoes are fork-tender.

Carefully scoop out half of the cooked potatoes and set them aside. In a blender, combine the roasted celery with the soup broth, blending until smooth. Return the blended mixture to the pot along with the reserved potatoes.

Bring the soup back to a gentle boil and add the 1 cup of elbow pasta. Cook until the pasta is al dente, about 8-10 minutes, stirring occasionally.

Ladle the warm soup into bowls. Personalize with optional garnishes like fresh dill, a sprinkle of red pepper flakes, or a drizzle of extra virgin olive oil.