Preheat oven to 350°F.
Grease a 9" x 13" pan.
Place the flour, baking soda, baking powder and pumpkin pie spice into a bowl and stir to combine.
Cream together the butter and cream cheese in a large bowl with a mixer.
Add in the Fructevia and mix to combine.
Mix in the canned pumpkin.
Stir in the egg.
Scrape down the sides of the bowl.
In small batches mix in the dry ingredients until combined.
Spread the dough into the prepared pan.
Bake for 20-25 minutes.
Remove from oven and let cool completely.
Place the flour and cornstarch into a small saucepan.
Over medium heat whisk the milk into the flour and corn starch.
Heat until the mixture begins to boil while stirring.
Lower the temperature some and continue whisking until the mixture thickens. It should be the consistency of paste.
Pour the mixture into a bowl and let cool. You can cool it in the refrigerator for an hour or two if you don't want to wait but it must be completely cooled.
In the bowl of a stand mixer fitted with the whisk attachment cream together the butter, sugar and vanilla on medium-high speed.
Scrape down the sides and bottom of the bowl and then add in the cooled flour mixture.
Beat on medium-high speed for 7-10 minutes. The longer you beat the mixture the creamier and fluffier it will become.
Frost the cooled blondies.
This dough is very thick and sticky. To spread it evenly in the pan you will want to use a greased spatula.
Serving Size 1 blondie
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.