In a stockpot, heat olive oil over medium heat. Add pancetta and cook out all the fat. Add garlic and shallot, saute until tender. Add onion, celery and carrot, saute until tender.
Stir in split peas; combine well. Add chicken stock, thyme, salt and pepper. Bring to a boil. Reduce heat and simmer until peas are soft and are falling apart. Remove from heat and cool slightly.
Place a few ladles of soup into a blender and add a couple handfuls of spinach. Blend until spinach is incorporated. Place soup in a second pot. Repeat with remaining soup and spinach. Warm soup over very low heat.