Preheat the oven to 400°F.
Melt the butter in a 6-quart stock pot over medium-high heat. Add the onions and celery. Season with salt and pepper. Sauté until the vegetables are soft, about 4 minutes.Add the bay leaf and garlic. Add the stock and parsnips and bring the mixture to a boil. Reduce the heat to medium and simmer, uncovered, until the parsnips are very soft and the mixture has thickened and creamy, about 1 hour.
Remove the soup from the heat. Discard the bay leaf.
Using a hand-held blender, puree until smooth. Stir in the cream. Season with salt and pepper.
In a small sauté pan, over medium heat, render the ham until crispy. Fry the potatoes until crispy and brown, about 3 to 4 minutes. Remove the potatoes from the oil and drain on paper towels. Season with salt.
Remove the bacon and drain on paper towels.
To serve, ladle the soup into serving bowls. Garnish with the crispy potatoes, bacon and chives.
Makes 8 servings