Ultimate Vegetable Stock

1. Combine onions, garlic, shallots, celery, and carrot in 8-quart stockpot or Dutch oven; spray vegetables lightly with vegetable oil spray and toss to coat. Cover and cook over low heat, stirring frequently, until pan bottom shows light brown glaze, 20 to 30 minutes. Add leeks and increase heat to medium; cook, covered, until leeks soften, about 10 minutes. Add 1-1⁄2 cups boiling water and cook, partially covered, until water has evaporated to a glaze and vegetables are very soft, 25 to 35 minutes.
2. Add parsley stems, bay leaves, salt, peppercorns, and remaining 7 cups boiling water. Increase heat to medium-high and bring to simmer; reduce heat to medium-low and simmer gently, covered, to blend flavors, about 15 minutes.
3. Add collard greens, cauliflower, thyme, lemon grass, and scallions. Increase heat to medium-high and bring to simmer; reduce heat to low and simmer gently, covered, to blend flavors, about 15 minutes longer. Strain stock through large strainer into large bowl or container, allowing stock to drip through to drain thoroughly (do not press on solids). Stir vinegar into stock. (Stock can be refrigerated for up to 4 days or frozen for up to 2 months.)

BRUISING LEMON GRASS
To bruise lemon grass, smack stalk with back of large chef’s knife.