To prepare the crust

1. Preheat the oven to 350 degrees. Lightly spray 6- 4″ tart pans with removable bottoms with baking spray and set aside.
2. Cream together the butter and sugar, about 1-2 minutes on medium speed. Scrape the sides of the bowl and add the vanilla. Add the flour and salt all at once and stir on low speed until large crumbles begin to form.
3. Divide the dough between the 6 tart pans and lightly press the dough out evenly on the bottom and up the sides. Place on a sheet pan and in the freezer for the dough to set up for about 10 minutes.
4. Bake in the preheated oven for 15 minutes. Once removed from the oven, carefully press out the bottom or any areas where the dough may have gotten droopy in the pans. Be sure to do this while it is still warm from the oven! Set aside while you prepare the filling.

To prepare the filling

1. Cream the cream cheese in the bowl of a stand mixer on medium speed for about 2 minutes, or until smooth and creamy. Add 1/2 of the can of sweetened condensed milk and beat briefly to combine, scraping the bowl as needed. Add 1 egg, the vanilla, and salt, beating together to combine. Set aside 1/2 cup of this mixture in a medium sized bowl.
2. To that 1/2 cup of cream cheese mixture, add the pumpkin, the rest of the sweetened condensed milk, an egg and the egg yolk, and the pumpkin pie spice. Beat to combine, scraping the bowl as needed.
3. Pour 1/4 cup of the pumpkin mixture in each of the cooled tart shells, and drizzle 3 tablespoons of the cream cheese mixture over top. Drag a knife through the filling to create swirls, if desired.
4. Place each tart pan on a sheet pan and bake in the preheated oven for 15 minutes or until the outer edge of the tart has set well. Allow to cool briefly on the counter for about 30 minutes and then place in the fridge to cool completely. Serve each tart with a sprinkling of hazelnuts and a dollop of whipped cream, if desired.