50 littleneck clams (3 pounds, 8 ounces total), scrubbed
2 cups water
2 cups dry white wine (such as Sauvignon Blanc)
2 (1 ounce each) thick-cut bacon slices, finely chopped (1/2 cup)
1 medium-size (10 ounces) yellow onion, chopped (about 1 cup)
1 medium-size (8 ounces) green bell pepper, seeded and chopped (about 1 cup)
2 medium (about 4 ounces total) carrots, peeled and chopped (about 3/4 cup)
2 medium (about 2 ounces total) celery stalks, chopped (about 3/4 cup)
4 garlic cloves, minced (about 1 tablespoon)
2 teaspoons fresh chopped thyme, plus more for garnish
¼ teaspoon crushed red pepper
1 ½ pounds baby Yukon Gold potatoes, unpeeled and quartered
2 teaspoons kosher salt
1 dried bay leaf
1 (14 1/2-ounce) can fire-roasted diced tomatoes
Black pepper
Place clams, water, and wine in a medium-size Dutch oven. Cover and bring to a simmer over medium-high; simmer until clams have opened, about 15 minutes. Remove from heat. Remove and discard any clams that did not open. Set a fine mesh strainer lined with cheesecloth over a large heatproof bowl; pour clam mixture through strainer into bowl. Remove half of the clams from shells, and roughly chop (you'll have about 1/4 cup). Reserve remaining clams in shell and clam broth separately (you'll have about 5 cups broth). Rinse Dutch oven, and wipe dry.
Return Dutch oven to medium heat. Add bacon; cook, stirring often, until browned, about 8 minutes. Using a slotted spoon, transfer bacon to a paper towel-lined plate to drain. Add onion, bell pepper, carrots, and celery to drippings in Dutch oven; cook, stirring occasionally, until tender, 8 to 10 minutes. Add garlic, thyme, and crushed red pepper; cook, stirring constantly, until fragrant, about 30 seconds.
Add potatoes, salt, bay leaf, and reserved clam broth to mixture in Dutch oven; bring to a boil, partially covered, over medium. Boil, stirring occasionally, until potatoes are tender, 15 to 20 minutes. Using a wooden spoon, gently mash some of the potatoes to thicken broth. Stir in tomatoes, chopped clams, clams in shell, and bacon; cook, stirring occasionally, until heated through, about 5 minutes. Remove and discard bay leaf. Garnish with black pepper and additional thyme.
