How to Make It
Preheat the oven to 350°. On a baking sheet, toss the bread with the 2 tablespoons of olive oil and toast until golden and crisp, stirring once or twice, about 10 minutes. Season with salt and white pepper.
Meanwhile, in a large saucepan, heat the canola oil. Add the onion and cook over low heat, stirring, until softened, 6 minutes. Add 6 cups of water and bring to a boil. Simmer over moderately low heat until the water is reduced to 4 cups, 20 minutes. Add the peas and simmer for 4 minutes. Add the spinach and cook until wilted, about 1 minute.
Strain the vegetables, reserving the cooking liquid. Transfer the vegetables to a blender; add 1 cup of the cooking liquid and puree until very smooth. Return the puree to the same saucepan and stir in additional liquid until it reaches the desired consistency. Bring the soup to a simmer, then ladle into bowls. Garnish with the ham, croutons, chives and a drizzle of olive oil.