Nebraska Sweet Corn and Clam Chowder

Name: Nebraska Sweet Corn and Clam Chowder
Ingredients: 2 tablespoons unsalted butter; 1 small yellow onion, chopped finely, plus 2 yellow onions, cut into medium dice; 1 bay leaf; 1 spring fresh thyme; Salt; 1 cup dry white wine; 32 clams; 1/4 cup olive oil; 1 cup medium-diced celery (about 3 ribs); 1/8 teaspoon cayenne, or more, to taste; 1 herb sachet (see note); 1 tablespoon all-purpose flour; 2 cups frozen sweet corn, thawed; 1-1/2 cups heavy cream; 3 russet potatoes, peeled and cut into medium dice; 1/2 cup bacon lardons (see note)