For the blondies:

• Heat your oven to 350F. Line a 9X13 baking pan with foil. Select a piece that's long enough to extend beyond the end of the baking dish on both ends. That will help you get it out of the pan once it cools.
• Place the 1 cup of walnuts in a food processor and pulse. You want the texture to still be course, but not flour-like. Combine the processed walnuts, flour, baking powder, baking soda and salt in a bowl and stir.
• In a separate bowl combine the margarine and brown sugar and use a mixer to beat until light and fluffy. Create a well in the middle of the mixture and combine the ground flax seeds, corn starch, soy milk, apple cider vinegar, vanilla and rum (or rum extract). Stir this together until combined and then using the mixer slowly incorporate it into the rest of the batter.
• Add the dry ingredients to the wet and then stir until just combined. Fold in the half cup of chopped walnuts.
• Pour the batter in your prepared pan and bake for 30 - 35 minutes, or until lightly brown. Place on a rack to cool.
• While you're waiting for the blondies to bake, go ahead and make the Peanut Butter White Chocolate Topping. To do this, combine the coconut butter and coconut oil in a microwave safe bowl. Microwave in 8 second increments until the mixture has melted. Stir together and add the PB2 and 3 tablespoons powdered sugar and stir again until combined. Take a taste. This is plenty sweet for me, but if you like it a little sweeter, you can add another tablespoon of powdered sugar. If you don't have PB2 on hand, feel free to sub with 1 tablespoon of peanut butter.
• When the blondies have cooled, grip both ends of the foil and lift them out of the pan. Cut into bars and serve warm topped with ice cream drizzled with the Peanut Butter Coconut Topping.