Preheat the oven to 350°F.

For the crust, in a medium bowl, combine the flour, oats, salt, spices and chopped walnuts. Make a well in the center of the bowl, and pour in the cooled melted butter. Stir until the dough comes together, slightly. Pour the crust into a 9-inch springform pan. Using your hands and fingers, press the oatmeal cookie crust down firmly to ensure all holes or cracks are covered. Bake for about 15 to 20 minutes or until the edges are just starting to brown. Remove from the oven and allow to cool completely before proceeding.

To make the cinnamon swirl filling, in a small bowl, combine the brown sugar, cinnamon and melted butter. This will be chunky, don't worry about it, we'll fix it later. Set it off to the side.

To make the cheesecake filling, in a large mixing bowl, cream together the cream cheese and the granulated sugar, until smooth. Add the milk and stir until combined. Mix in the eggs, one at a time, making sure to blend completely after each addition. Add the sour cream, vanilla extract, and flour and mix once again. Scrape down the bottom and sides of the bowl and stir until the filling is completely smooth and lump free.

Spoon about a ¼ cup of the batter into the cinnamon swirl filling, and stir until smooth.

Pour the remainder of the cheesecake filling into the springform pan over the cooled crust. Dollop the cinnamon swirl filling on top and swirl with a wooden skewer or butter knife. It doesn't have to be perfect or precise, just swirl the cinnamon filling into the cheesecake batter.

Place the cheesecake onto a baking sheet and bake in a 350°F oven for 1 hour. Turn off the oven and allow the cheesecake to sit in there until it's completely cooled down. About 4 hours. DO NOT OPEN THE OVEN DOOR! This will prevent the cheesecake from cracking on the top. Do not even peek inside. Keep the door closed.

Once the cheesecake has cooled down, cover it with plastic wrap and place in the fridge to chill overnight (or at least 3 hours). I like my cheesecake super cold, so I leave it there overnight. But if you make it early on in the morning, you should be fine by dinner time! Run a knife along the edge of the pan, and remove the sides of the pan. Cut the cheesecake into wedges and serve with a dollop of fresh whipped cream and a dusting of ground cinnamon. Enjoy!