In a large pot, heat the oil over medium-high until shimmering. Add the garlic and cook until toasted, 1 minute. Add the pork, season with 1 1/2 tablespoons salt and 1/2 teaspoon pepper and cook, stirring occasionally, until lightly browned, about 4 minutes. Add the tamarind, onion, fish sauce, serrano chiles and 10 cups water, and bring to a boil over high.
Step 2
Once the mixture comes to a boil, lower the heat to medium, cover and simmer until the pork is softened but not fully tender, about 1 1/2 hours.
Step 3
Stir in the daikon, cover and continue to simmer until daikon is tender and the pork is yielding, about 30 minutes.
Step 4
Uncover and discard the chiles. Add the long beans, eggplant, tomatoes and spinach and cook, stirring occasionally, until the vegetables are tender, about 20 minutes.