Preheat oven to 430(220C). Prepare pumpkin and place into a non stick baking tray. Drizzle oil and sprinkle sugar and nutmeg over chunks. Add seasoning. Mix well with hands. Roast for 20-22 minutes, tossing occasionally.
Once pumpkin is cooked turn oven to 350(180C). Line a 11”x7” baking dish with parchment paper. Evenly place pumpkin and kale into dish.
In a large bowl beat eggs, cheese, mustard and season. Pour over pumpkin and kale. Place sage leaves over top of frittata. Press down slightly so that they stick.
Place into oven for 20 minutes. Pull frittata out and sprinkle with Parmesan and place back into oven for 10-15 minutes of until cooked. To check if frittata is cooked make a small hole in the centre with a pairing knife. Push down and if uncooked egg squirts out it will need to be cooked for longer. Allow to stand for 5 minutes.
Will keep for up to 3 days when left in an airtight container in the fridge.