Preheat the oven to 350°F. Line an 8x8 glass baking pan with parchment paper.
Put all of the crust ingredients into a food processor. Cut the butter up into teaspoon size pieces. Pulse until the dough turns to crumbles and bunches together slightly.
Pat the dough into the 8x8 glass baking dish and press it out so that it covers the bottom of the pan.
Bake for 20 minutes. I like to pat down the edges with a spoon as soon as the crust comes out of the oven to make the edges flatter and more even.
Pumpkin filling
In a food processor, combine all of the pumpkin filling ingredients. Pulse until smooth.
Pour the pumpkin filling on top of the crust. Make sure it spreads out evenly. Bake for 40-45 minutes. The center should be firm and not jiggle. Allow the bars to cool before frosting.
Egg White Frosting
In a small saucepan, bring the honey and apple cider vinegar to a boil over low heat. Stir occasionally.
While the honey mixture is being brought to a boil, beat the egg white until stiff peaks form.
Once the egg white is stiff, slowly pour in the boiling honey mixture, beating constantly. Continue to beat the frosting until it holds it’s shape (approx. 3-4 minutes).
Frost the pumpkin bars. Cut and serve! Store the bars in the fridge.
Cream Cheese Frosting
Combine all of the ingredients in a food processor. Pulse until smooth and thoroughly combined. Spread over the bars. Store in the fridge.
Notes
The frosting is a boiled frosting made out of egg white, so it will not hold it's shape after 1 day. The bars still taste delicious though even after the frosting has dissolved!