Special equipment: baking beans or pie weights
Preheat the oven to 400 degrees F.
Line the pie crust with parchment paper, fill with baking beans or pie weights and bake for 15 minutes. Carefully remove the baking beans and parchment and continue to bake until golden brown, 10 to 13 minutes more. Allow to cool to room temperature before filling.
Lower the oven temperature to 350 degrees F.
Meanwhile, in a mortar and pestle or food processor, grind the spinach, parsley, sage, mint and marjoram with 1 teaspoon salt until a very coarse paste forms. If it doesn't form into a paste, add 1 tablespoon water.
In a large bowl, whisk together the eggs, melted butter and herb paste until combined. Stir in 1 cup of the cheese.
Line the pie crust with the sausage, pour in the egg mixture and top with the remaining 1/2 cup cheese. Bake until the center is set and the top is dark golden, 45 to 55 minutes. Cool at room temperature for 1 hour before serving.