Melt butter in a medium-size saucepan over medium heat. Add the asparagus and cook for 2 minutes stirring occasionally. Add the ham and cook for another 2 minutes until ham is lightly browned.
Scatter the asparagus and ham over the yogurt filling.
Combine egg and 1 teaspoon water. Beat vigorously with a fork until well combined. Brush egg mixture over the crust for a nice shiny finish.
Bake for 10-12 minutes until filling is set. Sprinkle with fresh thyme leaves for garnish.
See Café Tips for more detailed instructions.