Heat oil in large saucepan or Dutch oven over medium-high heat. Add onion and fennel, and cook 7 to 10 minutes, or until beginning to turn deep brown, stirring occasionally. Add white wine, and stir to deglaze pan, scraping up any browned, stuck-on bits.Stir in 4 cups water, pumpkin purée, potato, garlic, tomato paste, Italian seasoning, and 3 cups water. Season with 1 tsp. salt and ¼ tsp. black pepper, if desired. Cover, and bring to a boil. Reduce heat to medium-low, and simmer, covered, 30 minutes, or until potatoes and fennel are very tender.Purée soup in batches in blender or food processor until smooth, adding more water or broth if necessary to obtain desired consistency. Reheat as needed, and serve garnished with fennel fronds.