In large pot, over low to medium heat, cook onions, garlic and ginger in 2 tablespoons of oil for about 10 minutes until onions are translucent.
Meanwhile toast cumin and coriander seeds in saute pan over medium heat for about 3 minutes. Let cool. Add chiles and tomatoes to pot. In spice grinder, grind cumin and coriander seeds with white peppercorns. Add to pot along with turmeric. Stir for about 2 minutes then add sherry and cook until most of the wine has evaporated. Add vegetable broth and coconut milk. If possible, blend with stick immersion blender or allow to cool slightly and blend in standard blender in small batches. Strain through sieve with medium holes, not mesh. Return to pot and whisk in peanut butter. Add vegetables and cook until vegetables are soft to bite, but not mushy. Taste, and salt, as necessary.