Set your oven to 350° degrees and lightly grease a cookie sheet.
Using a mixer, combine 2 tablespoons of granulated sugar, 6 tablespoons of butter, and 4 tablespoons of brown sugar.
Beat until mixed.
Add one egg and beat again for a minute or two.
This time, add the oats, all-purpose flour, baking soda, baking powder, and salt.
Beat well, which should take a minute or two.
Pour the filling onto the cookie sheet.
Bake for 15 minutes.
Remove from the heat and let it rest.
Crush your now-prepared oat cookie into small pieces and transfer to a mixing bowl.
Add 3 tablespoons of butter and 1 ½ tablespoons of brown sugar.
Beat until consistent.
Transfer the mixture to a glass pie dish.
To prepare the filling, set your oven to 350 degrees.
In a mixing bowl, combine brown sugar and granulated sugar, dry milk powder, salt, and butter.
Give it a thorough mix.
Add whipping cream, egg yolks, and vanilla.
Whisk until combined.
Pour the filling mixture over the crust.
Bake for half an hour.
Remove from the heat and let it cool for an hour or two.