Ingredients
3 eggs
1 ¾ cup sugar
¾ cup butter, softened
1 tsp. vanilla
2 cups flour
12 oz. fresh blueberries (about 2 cups)
Preheat oven to 350°. With a mixer, beat the eggs and sugar about 5–7 minutes, until slightly thickened. The mixture should almost double in size. The eggs work as a leavening agent, so it’s important to beat them long enough. The mixture should form a ribbon when you lift the beaters out of the bowl. Add the butter and vanilla, and mix for 2 minutes more. Stir in the flour until just combined. Add the blueberries and mix by hand so they are distributed evenly throughout the batter..
Spread batter in a buttered 9 x 13 pan. Bake for 40–50 minutes until very lightly browned and a toothpick inserted near the center comes out clean. Let cool completely before cutting into small squares.