01 - Preheat the oven to 350°F. Grease a 9x13-inch baking pan and line with parchment paper.
02 - In a large mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, ground cinnamon, ground nutmeg, ground ginger, and ground cloves until evenly blended.
03 - In a separate bowl, beat together granulated sugar, light brown sugar, pumpkin puree, vegetable oil, eggs, and vanilla extract until the mixture is completely smooth.
04 - Gradually add the dry ingredients to the wet mixture, stirring gently until just combined and no dry streaks remain.
05 - Fold in mini chocolate chips, chopped toasted pecans or walnuts, and toffee bits or caramel pieces, using a spatula to distribute evenly.
06 - Pour the batter into the prepared baking pan and spread into an even layer.
07 - In a clean bowl, beat together softened cream cheese, granulated sugar, egg, and vanilla extract until smooth and creamy.
08 - Drop spoonfuls of the cream cheese mixture over the pumpkin batter. Using a butter knife, gently swirl the cream cheese through the batter to create a marbled effect.
09 - Bake on the center rack for 45 to 50 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs attached.
10 - Allow the cake to cool completely in the pan before slicing into squares. Serve as is, or finish with a dusting of powdered sugar if desired.