Dice the onion into 1/2-inch pieces, slice the celery ribs into 1/2-inch pieces, cut the carrots into 1/4-inch rounds, and mince the garlic cloves. Add all prepared vegetables to the slow cooker along with the split chicken breasts (skin-on and bone-in preferred—the skin and bones create a richer, more flavorful broth). Sprinkle the dried basil, dried parsley, dried thyme, bay leaf, and black pepper over the chicken and vegetables. Pour in 8 cups of water, making sure the chicken is mostly submerged. Cover and cook on high for 4 hours or low for 8 hours—the longer cooking time allows the bones to release more collagen and minerals, creating a deeply flavorful broth.

Once the cooking time is complete, carefully remove the chicken breasts and bay leaf from the slow cooker using tongs or a slotted spoon. Set the chicken aside on a cutting board and discard the bay leaf. Let the chicken cool slightly (just 2-3 minutes) until it's cool enough to handle. I like to shred chicken while it's still warm—it comes apart more easily from the bones, giving you tender, delicate shreds rather than tough, stringy pieces.

Using two forks or your hands, shred the chicken meat from the bones, discarding the bones and skin. Break the meat into bite-sized pieces and return the shredded chicken to the slow cooker. Stir well to distribute the chicken evenly throughout the broth.

Add the 6 oz of wide egg noodles directly to the slow cooker and stir to submerge them in the broth. Cover and turn the heat to high. The noodles will cook in 8-10 minutes—stir them once or twice during cooking to prevent sticking. Wide egg noodles work beautifully in this soup because they're hearty, absorb the broth flavor, and add a comforting richness to each spoonful.

Once the noodles are tender, taste the soup and season with salt—I recommend starting with 1 tablespoon of Diamond Crystal kosher salt, then adjusting to your preference (remember that the long cooking time concentrates flavors, so the broth may already have some saltiness). Ladle the soup into bowls and garnish with fresh parsley if desired for a pop of color and brightness that cuts through the richness of the broth.