In a large pot, combine chicken stock, lemongrass, ginger, and garlic. Bring to a boil, then reduce heat and simmer for 15 minutes to infuse the flavours.

Add the chicken breasts to the broth and poach gently over medium-low heat for 18-22 minutes, until the internal temperature reaches 74°C when checked with a meat thermometer.

While chicken poaches, prepare soft-boiled eggs by lowering eggs into boiling water for 7 minutes, then transferring to an ice bath. Peel when cool.

Remove cooked chicken from broth and let rest for 5 minutes, then slice or shred into bite-sized pieces.

Strain the broth through a fine-mesh sieve, discarding the aromatics. Return broth to pot and stir in fish sauce, soy sauce, lime juice, and brown sugar.

Add sliced shiitake mushrooms to the broth and simmer for 3 minutes until tender.

Add sugar snap peas and cook for 2 minutes until bright green and crisp-tender.

Divide baby spinach among four large serving bowls. Ladle hot broth and vegetables over spinach, allowing the heat to wilt the leaves.

Top each bowl with sliced chicken and a halved soft-boiled egg.

Garnish with spring onions, fresh coriander, and sliced chilli if desired. Serve immediately with lime wedges on the side.