Ingredients 

440 grams soft white flour 

316 grams unsalted butter

400 grams brown sugar

200 grams fine white sugar

4 cold eggs

2 tbsp vanilla

1 tsp salt

Makes one 9”x13” pan

Instructions

Melt the butter over low heat, then place the melted butter into a measuring cup or bowl to cool. 

Line a 9” x13” anondized aluminum pan with a parchment sling, cutting the parchment just above the sides of the pan. The type of pan is very important. Do not use a glass or dark/non-stick pan as they will affect the texture of the blondies negatively.

Preheat the oven to 350f.

Place the eggs, sugars, vanilla and salt in the bowl of a stand mixer fitted with the whisk attachment and whisk on medium high speed (#8 setting) for 8-10 minutes. Because timing can vary based on the power of the mixture and the ambient temperature, look for visual cues of doneness- the eggs should be pale, thick and fluffy. You want the maximum amount of air possible whipped into the eggs. 

Once the eggs are done, turn the speed down to low and add the melted and cooled butter. It doesn’t need to be well incorporated as the goal is to keep as much air in the eggs as possible.

Add the flour all at once and mix until just incorporated slightly. Finish mixing by hand; there can be large streaks of flour in the batter. Do not overmix. 

Pour the batter into the parchment-lined baking pan and place in the center of the oven. Bake for 35 minutes, or until a toothpick comes out mostly clean.

Place the pan on a cooling rack and let cool completely before using the parchment sling to remove the blondie from the pan. Slice and serve cool.