Preparation

1. Insert the metal blade. With the machine running, drop the garlic through the feed tube and process to finely chop.
2. Scrape the work bowl.
3. Add the leeks and pulse to chop, about 10 pulses.
4. Place 6-quart stockpot over medium heat and add the olive oil.
5. When the olive oil is hot, stir in the chopped leeks and garlic.
6. Sweat the vegetables over medium low heat so that they become soft. Stir occasionally so that they do not pick up any color.
7. While the leeks are cooking, replace the chopping blade with the slicing disc assembly.
8. Peel and seed the squash; cut to fit the feed tube. Slice the squash.
9. Add the sliced squash into the stockpot with the leeks and garlic; stir well. 
10. Add the salt and pepper. Cook for an additional 5 minutes.
11. Add the wine to the pot.
12. Bring to a simmer and let the wine reduce by half.
13. Add the chicken broth and nutmeg. Bring soup to a low boil.
14. Reduce heat and let simmer until squash is very soft and is easily pierced with a knife, about 20 minutes.
15. Strain the solids from the cooking liquid, reserving the cooking liquid.
16. Transfer half of the cooking liquid to a clean pot and reserve.
17. Insert the metal blade. In two batches, add the solids to the food processor and process to purée, 2 to 3 minutes. Scrape the work bowl to insure the mixture is homogenous.
18. Return the puréed solids to the cooking liquid and stir to incorporate.
19. Add the lemon juice.
20. Stir in reserved cooking liquid to obtain desired consistency.
21. Taste and adjust seasoning.
22. If using the heavy cream, stir in last and bring to a simmer.