Step 1

Preheat the oven to 375 degrees Fahrenheit (190 degrees Celsius) with a baking tray on the center rack.

Step 2

In a large mixing bowl, whisk the eggs for 20-30 seconds. Add the half and half, salt, pepper, onion powder, and mustard (if using). Whisk until blended.

Step 3

Stir the diced ham, 3/4 cup of cheddar cheese, and all of the Swiss cheese into the egg mixture. Pour the filling into the empty pie crust and sprinkle the remaining cheddar cheese over the top.

Step 4

Carefully place the quiche onto the hot baking tray. Bake for 40-45 minutes or until the quiche is set and the top is golden brown.

Step 5

Remove the baking tray from the oven and let the quiche cool for 10-15 minutes. Serve warm, at room temperature, or cold.