Sauté the onion and garlic gently in the olive oil till soft.
Cook the spinach in boiling water and drain well.
Combine the spinach and the onion and place in a blender and blend until smooth.
Stir in the crème fraÎche and season with salt and pepper.
Fry the diced pancetta and breadcrumbs and sprinkle over the puréed spinach.
The puréed spinach can be prepared in advance, as can the pancetta and breadcrumb mixture.