Preheat the oven to 180°C.
Arrange the cubed bread in a small roasting tray. Melt the butter in a large heavy-based saucepan over a medium heat. Sauté the onion for 5-6 minutes until it starts to soften.
Add the peas, stir and cover with the stock. Bring to the boil and reduce to a simmer and cook for 5 minutes. Place the roasting tray in the oven for 8-10 minutes until coloured and crispy. Remove the soup from the heat and purée with a stick blender until smooth.
Keep over a low heat as you finish the garnishes. Heat a frying pan over a moderate heat until hot. Sauté the pancetta for 3-4 minutes until golden brown.Season the soup to taste then stir in the crème fraîche. Ladle into serving bowls. Garnish with the croutons and pancetta before serving.
Freezing and defrosting guidelines
Make the soup, then leave to cool at room temperature. Freeze (without garnishes or toppings) in a rigid container, leaving a bit of space for expansion, for up to 1-3 months. Reheat either from frozen or defrost in the fridge overnight. Once piping hot, add toppings or garnishes and serve.