Cheddar Corn Chowder

8 ounces bacon, chopped
1/4 cup olive oil
6 cups chopped yellow onions (4 large onions)
4 tablespoons (1/2 stick) unsalted butter
1/2 cup flour
2 teaspoons kosher salt
1 teaspoon freshly ground black pepper
1/2 teaspoon ground turmeric
12 cups chicken stock
6 cups medium-diced white boiling potatoes, unpeeled (2 pounds)
10 cups corn kernels, fresh (10 ears) or frozen (3 pounds)
2 cups half-and-half
8 ounces sharp white cheddar cheese, grated

In a large stockpot over medium-high heat, cook the bacon and olive oil until the bacon is crisp, about 5 minutes. Remove the bacon with a slotted spoon and reserve. Reduce the heat to medium, add the onions and butter to the fat, and cook for 10 minutes, until the onions are translucent.

Stir in the flour, salt, pepper, and turmeric and cook for 3 minutes. Add the chicken stock and potatoes, bring to a boil, and simmer uncovered for 15 minutes, until the potatoes are tender. If using fresh corn, cut the kernels off the cob and blanch them for 3 minutes in boiling salted water. Drain. (If using frozen corn you can skip this step.) Add the corn to the soup, then add the half-and-half and cheddar. Cook for 5 more minutes, until the cheese is melted. Season, to taste, with salt and pepper. Serve hot with a garnish of bacon.