-butter -brown sugar -granulated sugar -egg -vanilla -rolled oats -flour -salt -baking powder -baking soda -milk powder -heavy cream -egg yolks -powdered sugar
In a stand mixer, cream together 6 Tablespoons of butter, brown, and granulated sugar at medium speed for 3 minutes until light and fluffy. Scrape down the sides of the bowl as needed. Beat in the egg and vanilla for another 2 minutes. Reduce the speed to low, and mix in the rolled oats, flour, salt, baking powder, and baking soda. Scrape down the sides.
Mix in the heavy cream and vanilla and beat for 2 to 3 minutes until fully incorporated, scraping down the sides. Keep the speed set to low as you add in the egg yolks. Mix this until the mixture is glossy, about 3 minutes. Once the cookie has completely cooled, break it up into pieces and put them in a food processor. Add the remaining 2 Tablespoons of softened butter and add this to the food processor. Pulse until crumbly.
Press the cookie crumbs into the bottom and up the sides of a 9 or 10-inch pie dish. Place the pie dish onto a baking sheet then pour the filling into the pie dish. Carefully transfer the baking sheet with the pie on it to the middle rack of the oven and bake for 15 minutes. Reduce the oven temperature to 325°F and bake for 15 more minutes.
Remove the pie from the oven and place the pie pan on a cooling rack and allow it to cool for 30 minutes. Then wrap it with tin foil and place it in the freezer for at least 2 hours, or overnight. Move the pie from the freezer to the fridge 1 hour before you are planning to serve it. Dust it with powdered sugar before serving.