Adjust rack to center of oven; preheat oven to 350 degrees F. Line a 13 by 9 inch pan (which must be at least 1-1/2 inches tall) with heavy-duty aluminum foil, shiny side up (alternatively, you can line the pan with two lengths of regular weight foil). Fold any excess foil back against the outer edges of the pan. Grease the foil lightly with vegetable shortening. Set aside.
Place chips in small bowl. Add about 2 teaspoons of the sifted, measured flour (it’s not necessary to measure this small amount). Stir the chips until they’re coated with flour and set aside. In another small bowl, combine remaining flour and salt; stir until mixed. Set aside.
In large bowl of electric mixer (preferably fitted with paddle beater), combine butter and sugars. Beat at a low speed until partially mixed. Increase speed to medium and beat 2 minutes, stopping halfway through to scrape down bowl and beater (scrape bowl and beater often throughout remaining mixing process to ensure complete blending of ingredients). Add corn syrup and vanilla; beat in both at a low speed.
Add eggs, one at a time, beating at a low speed after each addition just until incorporated. Once all eggs are in, increase speed to medium; beat 1 minute. At a low speed, gradually add flour, beating only until combined. Remove bowl from mixer. Add chips (and any flour at the bottom of the bowl); with large rubber spatula, fold in until evenly distributed. Batter will be stiff.
Spoon batter into prepared pan. Spread level, making certain batter is well-pushed into corners. Bake in preheated oven for 30 to 35 minutes, turning back-to-front once about halfway during baking time. Blondies will brown handsomely on top, with outer edges darker; center may rise higher than edges. Blondies are done when a toothpick inserted near center emerges with only a few moist crumbs still clinging to it. Do not overbake! Remove to cooling rack. Cool completely before cutting.
To cut, remove Blondies, still in foil, from pan; place on large cutting board. Gently peel back foil from all sides. Using a large, sharp, straight-edged knife, cut off and discard 1/4 to 1/2 inch from each side. Cut brownies into 32 bars (you can cut them smaller if you wish). Store airtight at room temperature for up to a day or so; freeze for longer storage.