Ingredients:

  • 250 g (2 cups) All-purpose flour
  • 3 g (½ tsp) Fine sea salt (for crust)
  • 113 g (8 Tbsp / ½ cup) Unsalted butter, cut into ½-inch cubes, chilled rock solid (for crust)
  • 60 g (4 Tbsp) Vegetable shortening, chilled rock solid
  • 75–90 ml (5–6 Tbsp) Ice water
  • 113 g (½ cup / 1 stick) Unsalted butter, melted and cooled slightly (for filling)
  • 200 g (1 cup, packed) Dark brown sugar
  • 175 g (¾ cup) Light corn syrup
  • 120 ml (½ cup) Whole milk
  • 100 g (1 cup) Old-fashioned rolled oats (not instant)
  • 2 large Eggs, lightly beaten
  • 5 g (1 tsp) Vanilla extract
  • 3 g (½ tsp) Ground cinnamon
  • 1 g (¼ tsp) Fine sea salt (for filling)

Instructions:

  1. Combine Dry Ingredients: Whisk the flour and crust salt in a large bowl.
  2. Cut in Fat: Use a pastry blender or fingers to cut the cold butter and shortening into the flour until the mixture resembles coarse sand with some pea-sized pieces of fat remaining.
  3. Add Liquid: Gradually drizzle in the ice water, 1 tablespoon at a time, until the dough just comes together. Do not overmix; the dough should look shaggy.
  4. Chill: Form the dough into a disc, wrap tightly in cling film, and chill in the refrigerator for at least 30 minutes.
  5. Roll and Fit: Roll the dough into a 12-inch circle. Carefully fit the dough into the 9-inch pie plate. Trim and crimp the edges neatly, then freeze the prepared crust for 15 minutes while you preheat the oven.
  6. Preheat Oven: Preheat oven to 190°C (375°F). Position the rack in the lower third of the oven.
  7. Combine Wet Ingredients: In a large bowl, whisk together the melted butter, brown sugar, corn syrup, milk, eggs, and vanilla until well combined and smooth.
  8. Add Dry Ingredients: Stir in the rolled oats, cinnamon, and filling salt. Allow the mixture to stand for 5–10 minutes so the oats begin to absorb liquid.
  9. Pour and Shield: Pour the filling mixture carefully into the chilled pie shell. Place the pie on a baking sheet.
  10. Initial Bake (High Heat): Bake at 190°C (375°F) for 15 minutes.
  11. Reduce Heat and Finish: Reduce the oven temperature to 175°C (350°F). Cover the exposed crust edges with a pie shield or foil strips. Continue baking for an additional 40–50 minutes.
  12. Test for Doneness: The pie is done when the edges are set and the centre has a slight wobble. A knife inserted halfway between the edge and the centre should come out mostly clean.
  13. Cool Completely: Remove the pie from the oven. Allow the pie to cool completely on a wire rack for a minimum of 3 hours before slicing. This is critical for the custard base to set.