A frittata is the perfect meal any time of day, cold or hot, eaten with a knife and fork or with your hands. It’s the type of dish a person is tempted to use as a receptacle for leftovers, throwing in bits of meat and cooked vegetables, wilted herbs and an old knob of cheese. It’s hard to go wrong with a frittata, but if you want to go really, really right, this is the recipe.
The sweet and earthy flavors of winter squash, leeks and Swiss chard swirl together here in a frittata with a creamy, custard-like texture. The secret to the heavenly texture is full-fat dairy; without it, frittatas often have the texture of a kitchen sponge. Dairy isn’t for everyone, but if you tolerate dairy well, then there’s no reason to abstain. Full-fat dairy  has more than just rich, delicious flavor to offer.
In this frittata recipe, crème fraiche adds amazing flavor and texture, although the same amount of yogurt, cream, or grated cheese can be substituted. And if this frittata has too many veggies for you and not enough meat, then go ahead and add some prosciutto or cooked bacon. You won’t be sorry.
Servings: 4 to 6
Time in the Kitchen: 1 hour 25 minutes
- 1 acorn or butternut squash
- 2 tablespoons melted butter (15 ml)
- 2 teaspoons finely chopped fresh rosemary (10 ml)
- 1 tablespoon extra virgin olive oil  (or butter) (15 ml)
- 1 leek, cut in half lengthwise and thinly sliced
- 3 large Swiss chard leaves, cut into thin strips (thick stems discarded)
- 12 eggs 
- 1/2 cup crème fraiche (115 g)
- 1/4 teaspoon nutmeg (1.2 ml)
- Salt  and Pepper 
Preheat oven to 400 °F/204 °C.
Slice the squash in half lengthwise, from tip to stem. Scoop out the seeds and stringy middle. Cut each half into wedges that are ¾-inch to 1-inch (19 mm to 2.5 cm) thick. In a large bowl, pour melted butter over the wedges and sprinkle with rosemary. Toss to coat.
Spread squash out on a baking sheet. Roast, turning once, until both sides are browned and the flesh is tender, 30 to 40 minutes. When the squash is cool enough to handle, remove the skin and cut the flesh into ½-inch/13 mm cubes.
Turn the oven heat down to 350 °F/177 °C.
Heat the olive oil (or butter) over medium heat in a 10-inch/25 cm ovenproof skillet (ideally, well-seasoned cast iron). Add the leek and cook until softened but not browning, 3 to 5 minutes. Add the Swiss chard. Cook, stirring often, until completely wilted and all moisture evaporates, 3 to 5 minutes. Add the squash. Season with salt and pepper.
In a large bowl, whisk eggs, crème fraiche and nutmeg together. Pour into the 10-inch ovenproof skillet. Stir gently to make sure the vegetables are evenly distributed, the let the frittata cook undisturbed for 2 minutes.
Transfer the skillet to the oven and bake for 20 to 30 minutes, or until the middle is no longer runny but is still soft and just barely set. Cast iron retains a lot of heat and will keep cooking the egg once it’s out of the oven, so it’s a good idea to take the frittata out before it looks completely done.