In a mixing bowl, cream together ½ cup of softened unsalted butter with ½ cup of granulated sugar until light and fluffy, about 3–5 minutes. Add 1 egg yolk and 1 teaspoon of vanilla extract, mixing until combined. Gradually stir in 1 cup of all-purpose flour, followed by 1 cup of old-fashioned oats and ¼ teaspoon of salt, mixing until a dough forms.

Press the cookie crust dough evenly into a greased 9-inch pie plate, ensuring the bottom and sides are well covered. Refrigerate the crust for at least 30 minutes to firm up.

Preheat your oven to 375°F (190°C). Bake the chilled crust for 12–15 minutes or until lightly golden.

Pour 2 cups of whole milk and 1 cup of heavy cream into a saucepan. Heat over medium heat until tiny bubbles form around the edges.

In a large mixing bowl, whisk together 4 large eggs, 1 additional egg yolk, ¾ cup of granulated sugar, 1 tablespoon of vanilla bean paste, and the spices—¼ teaspoon ground nutmeg, ½ teaspoon ground cinnamon, and a pinch of ground cloves.

Slowly drizzle the hot milk and cream mixture into the egg mixture while whisking continuously to temper the eggs.

Pour the mixed custard through a fine mesh sieve into the pre-baked crust.

Bake the pie in a preheated oven at 325°F (163°C) for 40–50 minutes.

Once baked, let the pie cool on a wire rack for about two hours, then refrigerate for at least four hours to fully set.

For an optional praline sauce, combine 1 cup of chopped pecans, ½ cup of brown sugar, ¼ cup of corn syrup, 2 tablespoons of butter, a pinch of salt, and ½ teaspoon of cinnamon in a saucepan over medium heat.