Preheat your oven to 350°F. Grease a 9x9 inch pan with non-stick spray, then set it aside.

In a medium bowl, combine the flour, pumpkin spice, cinnamon, salt, and baking soda. Stir and set aside.

In another large bowl, beat the butter, granulated sugar, and brown sugar until fluffy.

Add in the egg yolk, pumpkin purée, and vanilla to the butter-sugar mixture. Mix well.

Gradually add the dry ingredients to the wet mixture, being careful not to over-mix. Fold in the white chocolate chunks and toffee bits.

Pour the batter evenly into the greased baking pan and spread it out to the edges.

Bake for around 25 minutes, or until a toothpick inserted into the center comes out clean or with slightly moist crumbs.

Let the blondies cool completely before slicing into squares and serving.