Preheat the oven to 180C/350F and line a 6 x 6-inch pan with parchment paper and set aside.
Add all your ingredients into a high speed blender, food processor or large bowl and mix until fully immersed and a thick batter is formed.
Transfer brownie batter to loaf pan and bake for 12-15 minutes, or until a skewer comes out just clean.
Allow the brownies to cool in the pan completely before adding frosting.
* Pumpkin pie mix has added spices and sugar in it. If you only have pumpkin puree (unsweetened), add at least 2 tablespoons sugar or maple syrup. TO STORE: Leftovers must be stored in the refrigerator, covered, and they will keep well for up to one week.TO FREEZE: Place brownies in an airtight container and store them in the freezer for up to 6 months.