*Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.
**Nutrient information is not available for all ingredients. Amount is based on available nutrient data.
(-)Information is not currently available for this nutrient. If you are following a medically restrictive diet, please consult your doctor or registered dietitian before preparing this recipe for personal consumption.
Preheat oven to 350 degrees F (175 degrees C). Grease an 8x8-inch baking pan.
Whisk 1 1/3 cups flour and white sugar together in a bowl; cut in 1/2 cup butter with a pastry blender until mixture resembles coarse crumbs. Press flour mixture evenly into bottom of prepared pan.
Bake in the preheated oven until light golden, about 10 minutes; remove base from oven to cool slightly, leaving oven on, about 5 minutes. Sprinkle base evenly with raisins and walnuts.
Beat eggs well in a bowl with an electric mixer; beat in brown sugar until creamy, about 2 minutes. Beat 1/4 cup butter, vinegar, 1 tablespoon flour, and vanilla extract into sugar mixture just until combined; pour over base, covering raisins and nuts.
Bake in the preheated oven until bubbly, about 30 minutes. Allow to cool completely, about 30 minutes; cut into squares.