Place flour, salt and butter in a food processor. Pulse until mixture resembles coarse cornmeal. Combine eggs and ice water with a whisk in a small bowl before adding to flour mixture. Pulse until moist crumbs start to form, but no longer.

Roll dough into a ball, wrap in plastic wrap and refrigerator for 30 minutes or up to four hours.

Roll out dough to a 14 inch round. Fit into a 9-inch springform pan. Fold, press and arrange sides for even thickness.

Trim the top of the springform pan by using a knife, so that the crust is even around the entire circumference.

Preheat oven to 400 degrees.

Line crust with parchment; fill with dried beans, rice or pie weights. Bake 20 minutes, remove paper and beans. Bake until golden, approximately 10-15 minutes. Let cool.

Reduce oven to 375 degrees. Whisk eggs until smooth in a small bowl, then add the remaining ingredients until well combined. Mix in any variation of ingredients.

Ingredients for Gruyere and Spinach: 6 cups of lightly packed fresh spinach (stems trimmed). Sprinkle 1/2 cup grated Gruyère on top of the custard once it has been poured into the pie crust.

Pour custard into the cooled pie crust, stopping just short of the top. Be sure not to overfilled. If using the above ingredient amounts, it should be just enough.

Add the 1/2 cup of Gruyère. Bake 10 minutes; reduce oven to 325 degrees. Bake until filling is just set, or about an hour.