Preheat the oven to 180ºC, fan 160ºC, gas 4. Heat the oil in a small pan, add the spinach and cook until just wilted. Remove from the heat and stir through the crème fraîche.
Spoon the spinach mixture into a 250ml ramekin. Use the back of a spoon to make an indent in the middle of the mixture, and break the egg into it. Season with freshly ground black pepper and bake in the oven for 12 minutes until the egg white is opaque.
Meanwhile, toast the bread. Use heartshape cutters to stamp out a heart from each slice of toast, then butter the heart toasts.Serve alongside the baked egg with a little hollandaise sauce.