CRUST – 2 teaspoons cold water – 1 teaspoon cold cider vinegar – 1 1/2 cups all-purpose flour plus more for surface – 1/2 teaspoon salt – 4 ounces 1 stick cold unsalted butter, cut into small pieces – 4 ounces cold cream cheese cut into small pieces FILLING – 1 Tablespoon olive oil – 1 small onion chopped – 1 cup salmon cooked and broken into small pieces – 1 cup of potatoes cooked and cut into small pieces – 2 cups spinach cooked and cut into pieces (make sure all excess water has been squeezed from the spinach) – 1 teaspoon fresh tarragon – 4 eggs – 1/2 cup heavy cream – 1/2 cup milk – salt and pepper to tasteI