Step 1

Position rack in upper third of oven; preheat broiler.

Step 2

Whisk eggs, scallions, cheese, pepper and salt in a large bowl.

Step 3

Heat oil in a large cast-iron skillet (or broiler-safe nonstick skillet) over medium-high heat. Add chard and chorizo (or pepperoni) and cook, stirring frequently, until the chard is wilted, 2 to 3 minutes. Stir in hash browns. Pat the mixture into an even layer in the pan.

Step 4

Pour the egg mixture into the pan and evenly spread to the edges. Cook over medium-high heat, lifting around the edges with a heatproof spatula to allow uncooked egg to flow under, until set around the edges, 3 to 4 minutes. Place the skillet under the broiler until the top is cooked and the eggs are slightly browned, 3 to 4 minutes. Let stand 5 minutes.

Step 5

To release the frittata from the pan, run the spatula around the edges, then underneath, until you can slide or lift it out onto a cutting board or serving plate. Cut into wedges and serve.