Whisk together egg whites with half and half. Add ham, cheese, green onions, salt, and white pepper. Pour into pie crust.
Brush some of the egg onto the crust. Cover loosely with foil and bake for one hour at 350˚F. 10-15 minutes before the end of the bake cycle (45 minutes into baking), remove foil cover and top with rosemary sprigs. Note: rinse rosemary sprigs under cold water and gently shake off excess water, then add to the top of the quiche. This prevents rosemary from burning. Leave uncovered to lightly brown the crust and toast the rosemary. Be careful! Oven and pan will be hot!
When done, remove from oven and let cool to touch before serving.
Notes
Bake until center no longer looks wet and there is no wobble when gently shaken.