In a medium mixing bowl, stir the peanut butter and 1 cup of water until well combined and set aside.
Heat the olive oil in a large pot over medium-high heat. Add the onions and a pinch of salt and cook for 3-4 minutes, stirring occasionally, or until softened and beginning to brown.
Add the garlic and ginger and continue cooking and stirring for 1 minute.
Add the curry powder and cayenne, if using, and continue cooking and stirring for 1 minute.
Add the remaining 2 cups of water, tomato paste, tomatoes, cauliflower, potatoes, zucchini, and peanut butter mixture. Bring to a boil and reduce the heat to medium-low. Cook for 25-35 minutes, stirring occasionally, or until the vegetables are tender. While the curry is cooking, prepare the Coconut Basmati Rice, if using.
Once the vegetables have cooked, add the peas and cook for an additional minute or until heated through. Serve hot with cilantro and Coconut Basmati Rice, if desired.