1. Preheat oven to 350 degrees Fahrenheit. Line a loaf pan with parchment paper and set aside.
2. Whisk all ingredients, except chocolate and flaky salt, until fully combined. Stir in chocolate, and pour into prepared pan. If desired, sprinkle an extra pinch of chocolate on top of the batter before baking.
3. Bake for 15-20 minutes, or until blondies look cooked around the edges and still slightly undercooked in the middle. Mine were perfect at 18 minutes.The batter will puff up in the oven, but will sink as it cools.
4. Let cool, and sprinkle with flaky salt, if using, before slicing and serving. Our leftovers never made it past 2 days, but they were delicious leftover for those 2 days. I imagine they would last well for 4-5 days at room temperature, if you can make them last that long.