Step 1

Preheat oven to 375°F. Place pie crust on a baking sheet. Melt butter in a large skillet over medium. Add chard and leek; cook, stirring occasionally, until mixture is tender, 6 to 8 minutes. Remove from heat. Let cool for 5 minutes.

Step 2

Whisk eggs, buttermilk, salt, and pepper in a large bowl. Add cooled leek mixture, cheese, and ham; fold until combined. Pour into piecrust.

Step 3

Bake until center of quiche is just set, 40 to 45 minutes. Remove from oven. Let cool for 10 to 15 minutes before slicing.