Add the spinach and toss over gentle heat until wilted.
Transfer the mixture to a food processor and pulse until finely chopped.
Add feta and pulse to combine.
Add in enough creme fraiche to make a soft dip and season to taste.
Serve with crostini etc.
Note: To make crostini - pan fry both sides of angle sliced slices of french bread in a little olive oil over a moderate heat until light golden brown, or bake lightly brushed with olive oil, slices of french bread.