Step 1Place the leeks, onion, celery, fennel, carrots, bay leaf, peppercorns, thyme, corncobs and water in a large stockpot and bring to a rolling simmer. Do not boil. Let the mixture simmer for 1 hour, partially covered.
Step 2Turn off the heat and let the mixture stand for 1 hour. Strain through a fine mesh sieve and store. Keeps for about 1 week, refrigerated.
Step 1In a large heavy-bottomed stockpot, cook the onion, bay leaf, carrots and celery in the olive oil over medium-low heat until the onion is translucent and the vegetables are tender.
Step 2Add the garlic, black-eyed peas and potatoes and cook for an additional 5 minutes.
Step 3Add the corn stock, bring to a simmer and simmer slowly for 20 minutes.
Step 4When the vegetables are almost tender, add the peas, corn and thyme. Continue to simmer for an additional 10 minutes.
Step 5Season with salt and pepper to taste and serve.