1.
Melt the butter in a large non-stick frypan over medium heat.
2.
Add onion and sweet potatoes and stir to coat. Cook, covered, for 8-10minutes, stirring occasionally, until sweet potato is just tender. Add spinach and cover for 30 seconds, then remove lid and stir until wilted. Sprinkle with blue cheese.
3.
Whisk the eggs and creme fraiche in a bowl until just combined, then pour over the potato mixture.
4.
Reduce heat to low, then cover and cook for 20-25 minutes or until set.
5.
Cut into wedges in the pan, then carefully lift out. Season and serve with a green salad.