Rosemary Spinach Mushroom Alpine Quiche Crust:8 Tbs. ice-cold butter, cubed into 1″ pieces2 1/4 cups all-purpose flour 1 Tbs. fresh rosemary, finely chopped1 large egg1 Tbs. apple cider vinegar3-4 Tbs. ice cold water Filling:3 Tbs. butter1 small sweet onion, finely chopped8 oz. baby bella mushrooms, sliced1 large portabella mushroom, sliced2 cups fresh baby spinach1 tsp….