Preheat the oven to 400 degrees F.

Heat a 10-inch oven-safe skillet over medium heat and 2 tablespoons of the butter. Stir in the butternut squash with a big pinch of salt and pepper. Cook for 5 to 6 minutes. Add the other tablespoon of butter. Stir in the diced onion and garlic and cook for 5 minutes more, stirring often. The squash should be tender at his point - if not, cook for a few more minutes until fork tender. Turn off the heat.

In a large bowl, stir together the eggs, cream, herbs and parmesan cheese. Stir in a pinch of salt and pepper. Whisk until combined.

Pour the mixture into the skillet with the squash. Stick the skillet in the oven and bake the frittata for 10 to 15 minutes, or until it’s set in the center. You want the eggs set - if they aren’t, bake it for another 2 minutes and check again.

In a bowl, toss the arugula with the olive oil and a pinch of salt and pepper.

Remove it from the oven and top with the arugula and shaved parmesan. Slice it into squares or wedges - whatever you prefer. This tastes great hot or cold! The leftovers from the fridge are great too.