To prepare the oatmeal cookie pieces

1. Preheat the oven to 350 degrees.
2. Stir together the flour, oats, baking soda, cinnamon, and salt until combined in a medium sized bowl.In a large bowl, cream the butter until smooth with an electric mixer. Add the sugar, beating until light and fluffy. Add the vanilla and eggs, beating well to combine thoroughly. Add the dry ingredients slowly and mix just until combined.
3. Pat out the dough into the bottom of an 8″x8″ baking pan and bake in the preheated oven for 30 minutes or until the dough at the center of the pan looks nearly done. Allow to cool at room temperature or in a fridge. Dice 1/2 of the pan into 1/2″ squares just before using. The remaining pieces can be stored at room temperature for 3 days or in the freezer for up to 2 months.

To prepare the cinnamon swirl filling

1. Combine the corn syrup, cinnamon, and sugar by stirring. Set aside until ready to use.

To prepare the ice cream

1. Preheat the oven to 350 degrees. Spread the oats out on a small sheet pan and toast in the preheated oven for 10 minutes. The oats should become fragrant but not burned.
2. Meanwhile, mix two tablespoons of the milk with the cornstarch in a small bowl. In a separate, medium-sized bowl, whisk the cream cheese and salt together until smooth.
3. In a 4 quart saucepan, combine the remaining milk, cream, sugar, corn syrup, and oats. Bring to a boil over medium heat and boil for 4 minutes. Using a fine mesh strainer, strain the oats from the milk mixture and discard. Pour the milk mixture back into the saucepan and return to the heat. Gradually whisk in the cornstarch slurry and bring back to a boil, stirring constantly. Mixture will thicken slightly and should coat the back of a spoon after about 1 minute. Remove from heat.
4. Whisk the milk mixture into the cream cheese mixture until smooth and without clumps. Pour the mixture into a gallon sized plastic bag and place it, sealed, in to the ice bath. Allow to chill until cold, adding ice as needed.
5. Once cold, pour the mixture into a prepared ice cream maker canister and prepare ice cream according to the manufacturer’s instructions.
6. Once ice cream is finished, smooth, and creamy, layer large spoonfuls into a dish (I use a loaf pan), drizzling with the cinnamon swirl filling and topping with cookie pieces as you layer in the ice cream. Once all of the ice cream has been layered in the dish with the cookies and swirl filling, drag a knife through the ice cream 5-6 times to swirl the components together. Cover and allow to freeze in the freezer for at least 6 hours prior to eating.