Toasted Sesame Crust:
2 cups all-purpose flour (use a gluten free blend if needed)
1 teaspoon salt
8 tablespoons (1 stick) unsalted cold butter, diced
1 egg, beaten
1/4 cup cold buttermilk or water
1/4 sesame seeds, toasted
Filling:
1 tablespoon butter or olive oil
1 small onion, finely diced
1/2 cup oil-packed sun-dried tomatoes, sliced
12 ounces fresh or frozen spinach, defrosted and squeezed dry if frozen
1/2 teaspoon dried thyme
1 teaspoon dried dill
pinch of salt and pepper
1 cup havarti cheese, shredded
3/4 cup sharp cheddar cheese, shredded
1/2 cup gruyere cheese, shredded
6 eggs
2 cup plain greek yogurt
1 cup milk
1/8 teaspoon nutmeg
3-4 ounces thinly sliced prosciutto
fresh thyme and flakey sea salt, for garnish