Step 1: Prepare the Aromatics. Heat a large pot over medium heat. Add a splash of oil and toss in the minced garlic and sliced shallots. Sauté for about 2-3 minutes until they become fragrant and translucent.
Step 2: Add Vegetables. Add the finely sliced carrots, bok choy, and mushrooms to the pot. Stir and cook for another 3-4 minutes until the vegetables soften slightly.
Step 3: Incorporate the Broth. Pour in the sodium-free chicken stock along with the red curry paste. Stir well to combine, ensuring the curry paste dissolves into the broth. Bring the mixture to a gentle simmer.
Step 4: Cook the Noodles. Add the Pad Thai noodles. Cook according to package instructions, about 3-5 minutes, until the noodles are tender but still have a slight bite.
Step 5: Add Shrimp and Seasonings. Stir in the peeled and deveined shrimp, ginger, sugar, and lemon juice. Cook for an additional 2-3 minutes, or until the shrimp turn pink and opaque.
Step 6: Final Touches. Remove the pot from heat. Taste the soup and adjust the seasoning if necessary. You can add more lemon juice for acidity or a pinch of salt for extra flavor.
Step 7: Serve and Garnish. Ladle the soup into serving bowls and garnish with chopped scallions. Serve hot and enjoy!