Coarsely chop the fennel bulbs and leeks, reserving the fronds of the fennel, minced, for garnish. Save the greens of the leeks for making chicken stock.
Heat olive oil in a large saucepan or soup pot. Add fennel, leeks, sea salt, pepper, and cumin. Sauté for 20 minutes, stirring often, until the veggies begin to soften.
Add cooked ground meat, chicken broth, cover, and simmer 20 minutes. Using an immersion blender, puree until smooth, or alternatively purée in small batches in food processor or blender.
Add salt and pepper to taste. Serve immediately topped with minced fennel fronds.