In a large saucepan, heat the canola oil.
Add the onion and cook over low heat, stirring, until softened, about 5 minutes.
Add 4 cups of chicken stock and bring to a boil.
Add the peas and simmer for 5 minutes.
Add the spinach and cook until wilted.
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.
Taste for seasoning. Add salt and pepper to taste.
Add 1/2 cup half and half.
Let soup cool and refrigerate at least 4 hours or overnight.
Pre-heat oven to 400 degrees.
Place prosciutto slices on a cookie sheet and bake for 8 minutes or until crisp.
Drain on paper towel.
Break prosciutto into pieces
Remove soup from refrigerator 1 hour before serving.
Ladle soup into bowls and garnish with prosciutto pieces.