Step 1: Prepare the Vegetables : Start by peeling the celery root. (Use a sharp knife or vegetable peeler to remove the knobby outer skin.) Dice the celery root, apples, potato, and onion into roughly 1-inch cubes for even cooking.

Step 2: Sauté the Aromatics : In a large soup pot or Dutch oven, melt butter over medium heat. Add the chopped onion and sauté until translucent (about 4–5 minutes). Stir in the garlic and cook for another 30 seconds until fragrant.

Step 3: Add the Celery Root, Apple, and Potato : Add the diced celery root, apple, and potato to the pot. Season with a pinch of salt and pepper. Stir well to coat the vegetables with butter and aromatics.

Step 4: Add the Stock and Simmer : Pour in the vegetable or chicken stock. Bring the soup to a gentle boil, then reduce the heat to a simmer. Cover and cook for 25–30 minutes, or until the vegetables are soft and easily pierced with a fork.

Step 5: Blend Until Smooth : Remove the soup from heat and let it cool slightly. Use an immersion blender to purée the soup until smooth and velvety. (Alternatively, transfer the soup in batches to a blender — blend until smooth and return to the pot.) Stir in the cream, if using, and adjust seasoning with salt and pepper to taste.

Step 6: Reheat and Serve :Gently reheat the soup over low heat until warm (don’t let it boil). Ladle into bowls and garnish with your favorite toppings — a drizzle of olive oil, cream, or crunchy croutons.