This is an adaptation of a tradition Italian-Peruvian Swiss chard pie called pastel de acelga. It's also known as tarta pascualina in other Latin American countries, like Argentina and Uruguay. You can make the filling up to a week in advance and assemble the pie the day before you plan to bake it. It's best served at room temperature. Note: It's important to remove the ribs from the chard, as they tend to release a lot of water and can make your crust soggy. If you cannot find Swiss chard, use frozen chopped spinach instead. —Carlos C. Olaechea
Melt the butter in a saucepan over medium heat. Add flour and whisk to combine. Cook this mixture over medium heat for about 5 minutes until you see it sizzle. Remove from heat and add all of the hot milk at once, whisking vigorously to combine. Place the saucepan back onto the burner and continue whisking until thickened. Add nutmeg, as well as salt and pepper to taste. Remove from the heat and set aside to cool.
Cook Swiss chard (or spinach) in a large pot with about 1/2 cup of water until thoroughly cooked but still green. Drain into a sieve and press out all of the liquid from the greens using a spoon. This step is vital so that you do not end up with a soggy crust. I find it helpful to place the cooked chard in a tea towel or cheesecloth and squeeze out the water that way. When You can no longer squeeze any liquid from the chard, set it aside in a separate bowl until ready to use.
In a large skillet or pan, heat 1 tablespoon olive oil over medium heat. Add the onion and fry until translucent. Stir in the garlic and cook for a couple minutes until fragrant. Splash in the vermouth and cook until it reduces slightly. Now add the chard to the pan and break it up with a spoon to combine with onions and garlic. Add all of the béchamel and Parmesan to the pan and stir to combine. Transfer the mixture to a bowl and cover the surface with plastic wrap to avoid a skin from forming.
Meanwhile, preheat oven to 400°F. Butter and flour a 9-inch springform (or regular) cake pan. (The springform makes un-molding the pie much easier later.)
If you need to, roll out your crust so that you have two discs. The top crust should be about 9 inches in diameter. The bottom crust should be wider with enough overhang to crimp the edges. Carefully place the larger disc into the cake pan, pressing lightly with your fingers so that it covers the entire surface. Add enough filling to reach the top of the pan. (It’s okay if it goes a little above.) Now place the top crust on top of the filling. Crimp the edges together and trim off any excess. Cut wide slits on the top crust to allow steam to escape.
Brush the top of the pie with the beaten egg and bake for 30 minutes on the middle rack until the top is golden brown. Remove from oven and carefully transfer to a cake rack to cool.
I was born in Peru to a Limeño father and a Texan mother. We moved to Miami when I was five, and I grew up in the "Kendall-suyo" neighborhood—often called the 5th province of the Inca Empire because of its large Peruvian population. I've been writing about food since I was 11 years old, and in 2016 I received a master's degree in Gastronomy from Boston University. A travel columnist at Food52, I'm currently based in Hollywood, Florida—another vibrant Peruvian community—where I am a writer, culinary tour guide, and consultant.