Heat the oven to 350°F. Pan-spray an 8 × 8-inch square baking dish.
For the cinnamon crust, in a large bowl, mix together the flour, sugar, cinnamon, and salt with a spatula until well combined. Mix in the melted butter and toss to combine. Transfer the mixture to the greased baking dish. Using your palm and fingertips, firmly and evenly press it in, covering the dish's bottom.
For the dulce de leche layer, pour all of the dulce de leche on top of the crust, spreading evenly to cover the bottom layer entirely.
For the pumpkin layer, in a large bowl, stir together the cream cheese, sugar, salt, and cinnamon until smooth. Stir in the egg, pumpkin, and vanilla and mix until smooth and well combined. Pour this mixture atop the dulce de leche, spreading evenly to all sides of the baking dish, covering the dulce layer entirely.
Bake at 350°F until the pumpkin top is set but still jiggles back at you, 40 to 45 minutes.
Cool completely in the pan. Cut into 9 squares. Store in an airtight container or plastic wrapped in the fridge for up to 2 weeks.
