01 -
Preheat the oven to 350F. Grease a 9-inch pie dish well with butter or nonstick spray.
02 -
Scatter the diced ham, 1 cup of the cheddar, and most of the green onions into the prepared dish. Save the remaining cheese and green onions for the top.
03 -
In a medium bowl, whisk the eggs, half-and-half, Dijon mustard, garlic powder, salt, and pepper until smooth and evenly blended.
04 -
Pour the egg mixture over the ham and cheese. Sprinkle the reserved cheddar and green onions over the surface.
05 -
Bake for 35-40 minutes, until the edges are puffed and golden and the center has a slight wobble. The center should reach 160F if checked with a thermometer.
06 -
Let the quiche rest for 10 minutes before slicing. Serve warm, room temperature, or chilled.