Rinse lentils well and add them to a large pot with enough water to cover by about 2 1/2 inches. Add crushed garlic clove and bring to a boil. Add salt, reduce heat and simmer 30-40 minutes. Turn off heat and let lentils cool in any remaining liquid.
 
Heat a soup pot over medium-high heat with olive oil, 2 turns of the pan. Add chopped garlic, fennel, leeks, celery, onions, bay, herb bundle, some salt and pepper, and cook partially covered for 7-8 minutes to soften, stirring frequently. Add stock, passata or purée, and tomatoes, breaking them up with a spoon or crushing them with your hands when you add them to the pot. Stir in cooled lentils; combine and simmer to combine flavors and until soup reaches desired thickness.

 
Remove bay and herb bundle, and serve in shallow bowls garnished with chili flakes and a swirl of EVOO.

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