5 dried Thai chiles
1 cup hot water 3 tablespoons canola oil
3 medium garlic cloves, smashed
1 pound ground pork
2 small plum tomatoes, chopped (about 1 1/4 cups)
1/4 cup soybean paste (such as Healthy Boy)
2 tablespoons fish sauce (such as Red Boat), divided
1 tablespoon granulated sugar
1 teaspoon paprika
1 bunch fresh cilantro
8 cups lower-sodium chicken broth
14 ounces uncooked dried
1/8-inch-wide banh pho rice stick noodles
2 cups zucchini ribbons (shaved using a Y-shaped peeler, avoiding and discarding squash seeds) (optional)
2 cups shredded napa cabbage (optional)
1/2 cup chopped fresh mint Black pepper, for garnish
Lime wedges, for serving
Wearing gloves, crumble Thai chiles into a medium-size heatproof bowl. Add 1 cup hot water; let stand 15 minutes. Drain chiles; discard liquid. Process chiles, oil, and garlic in a mini food processor until chiles are very finely chopped, about 30 seconds, stopping to scrape down sides of bowl as needed.
Heat a large skillet over medium. Add chile mixture; cook, stirring constantly, until fragrant, about 1 minute. Add pork; cook, stirring occasionally to break pork into small pieces, until browned, 6 to 8 minutes. Stir in tomatoes, soybean paste, 1 tablespoon fish sauce, sugar, and paprika. Cook, stirring occasionally, until tomatoes break down, 8 to 10 minutes. Reduce heat to low; cook, stirring occasionally, until liquid has reduced and pork is coated with sauce, 8 to 10 minutes.
Meanwhile, separate cilantro stems from leaves; tie stems together with kitchen twine. Chop leaves to yield about 1/2 cup; set aside for garnish. Stir together chicken broth, cilantro stems, and remaining 1 tablespoon fish sauce in a medium saucepan. Cover and bring to a simmer over medium. Uncover; remove and discard cilantro stems. Cover broth; keep warm over medium-low.
Prepare rice noodles according to package directions. Drain noodles, and divide evenly among 8 serving bowls (about 2/3 cup each). If using, add zucchini ribbons and cabbage to hot broth; cook over medium-low until just tender, 30 seconds to 1 minute. Using tongs or a spider, remove vegetables from broth, and divide evenly among serving bowls (about 1/2 cup each). Top each bowl with about 1/4 cup pork mixture and 1 cup hot broth. Sprinkle bowls evenly with mint and reserved chopped cilantro. Garnish with black pepper, and serve with lime wedges.
Note: Noodles can be cooked up to 4 hours in advance and held in cold water. Broth can be made up to 4 hours in advance. Pork mixture can be cooked and stored in an airtight container in refrigerator up to 3 days ahead.