Pasqualina or Spinach Pie

Ingredients

• – Pastry dough for 2 9-in. deep dish pies
• – 2 tbsp. olive oil
• – 2 10-oz. boxes frozen chopped spinach, thawed and squeezed of excess liquid
• – 1 onion, finely diced
• – 6 tbsp. Real California butter
• – 6 tbsp. all-purpose flour, or more as needed, plus more for the work surface
• – 1/8 tsp. ground nutmeg
• – 1 cup plus 1 tbsp. Real California milk, divided, or more as needed
• – 6 large eggs
• – Salt and pepper