In a large pot, heat 2 tablespoons of olive oil over medium heat until shimmering. Add thinly sliced garlic, julienned ginger, ground turmeric, red chili flakes, and crushed black peppercorns. Sauté these aromatics for 2-3 minutes.

Pour in 4 cups of warmed bone or vegetable broth, ensuring it is at a gentle simmer. Use a wooden spoon to scrape the bottom of the pot, capturing any flavorful bits.

Reduce the heat to low and add half of the large lemon, sliced thinly, into the broth. Allow it to simmer for 15-20 minutes.

Remove the pot from heat and stir in the juice from the other half of the lemon, plus a handful of chopped scallions. Season with salt to taste.

Ladle the soup into bowls and garnish with remaining chopped scallions. Serve hot.