- Preheat your oven to 350°F. 
- Line a 9x13 inch baking dish with parchment paper, leaving some overhang on the sides for easy removal. 
- To make the crust, mix the flour, oats, baking soda, and salt in a small bowl. 
- In a large bowl, beat the butter and sugars together on medium speed for about 1 minute. 
- Scrape down the sides of the bowl, then gradually fold in the dry ingredients until the mixture forms a moist, crumbly texture. 
- Press half of this mixture evenly into the bottom of the prepared baking dish. Reserve the remaining half for the topping. 
- Bake the crust for 14 minutes. 
- While the crust bakes, prepare the filling. Beat the cream cheese in a large bowl on medium speed for 1 minute. Add the sweetened condensed milk, egg yolk, vanilla, and pumpkin pie spice. Continue mixing until well combined. 
- Once the crust is baked, spread the pumpkin cream cheese filling evenly over it. 
- Drop spoonfuls of pumpkin puree over the filling and use a spoon to swirl it in gently. 
- Sprinkle the reserved oat and sugar crumble mixture over the top. Bake for an additional 23 minutes. 
- Let the bars cool completely in the pan before cutting to ensure neat slices.