For Cookie Pie : Adjust oven rack to middle position and preheat oven to 350°F (175°C). Grease pan or pie plate.
In a medium bowl, whisk together flour, cinnamon, salt, baking soda, and oats; set aside.
In the bowl of a stand mixer fitted with a paddle attachment, cream together brown sugar, sugar, and butter until creamy, about 3 minutes. Beat in egg and vanilla. Add dry ingredients and beat just until dough is evenly combined. Used a rubber spatula to fold in raisins.
Scrape batter into prepared dish and use spatula to smooth the top. Bake until golden brown on top and set in the middle, 20 to 25 minutes. Let cool 5 minutes then release from springform pan. Let cool completely.
For Icing : In a small bowl, whisk together confectioners sugar and heavy cream until smooth. Drizzle over pie. Serve.
