Cut the bread into thick slices and toast in a hot oven to make crispy rusks. Slice the mushrooms and sauté in a frying pan with the onion in a knob of butter. Season with salt and pepper, add chopped tomatoes and spinach, set aside. To make the scramble, break the eggs and whisk lightly with a fork. Mix in the cream and the butter, season with salt and pepper and place on a bain-marie over simmering water, whisking randomly, removing the solidifying eggs from around the bowl. Finish with a pinch of Cayenne pepper. Serve the scrambled eggs over the rusks and top up with the mushrooms.